__Additions made to Stata during version 6__

This file records the additions and fixes made to Stata during the life
of Stata version 6:

+---------------------------------------------------------------+
| help file contents years |
|---------------------------------------------------------------|
| whatsnew Stata 15.0 and 15.1 2017 to present |
| whatsnew14to15 Stata 15.0 new release 2017 |
| whatsnew14 Stata 14.0, 14.1, and 14.2 2015 to 2017 |
| whatsnew13to14 Stata 14.0 new release 2015 |
| whatsnew13 Stata 13.0 and 13.1 2013 to 2015 |
| whatsnew12to13 Stata 13.0 new release 2013 |
| whatsnew12 Stata 12.0 and 12.1 2011 to 2013 |
| whatsnew11to12 Stata 12.0 new release 2011 |
| whatsnew11 Stata 11.0, 11.1, and 11.2 2009 to 2011 |
| whatsnew10to11 Stata 11.0 new release 2009 |
| whatsnew10 Stata 10.0 and 10.1 2007 to 2009 |
| whatsnew9to10 Stata 10.0 new release 2007 |
| whatsnew9 Stata 9.0, 9.1, and 9.2 2005 to 2007 |
| whatsnew8to9 Stata 9.0 new release 2005 |
| whatsnew8 Stata 8.0, 8.1, and 8.2 2003 to 2005 |
| whatsnew7to8 Stata 8.0 new release 2003 |
| whatsnew7 Stata 7.0 2001 to 2002 |
| whatsnew6to7 Stata 7.0 new release 2000 |
| **this file** Stata 6.0 1999 to 2000 |
+---------------------------------------------------------------+

Most recent changes are listed first. Note: Starred (*) items mean the
update was made to the executable.

----- **more recent updates** -----------------------------------------------------

See whatsnew6to7.

----- **update 20nov2000** --------------------------------------------------------

On-line help and search index brought up to date for STB-58

----- **update 03nov2000** --------------------------------------------------------

biprobit had difficulty parsing the second equation when it was longer than 80
characters; in that case, if the first and second equations were identical
for the first 80 characters, **biprobit** would use the first equation as the
second equation, and so estimate a model which was not the one requested.
This has been fixed.

glm with **family(binomial)** would report an error if the dependent variable did
not vary even when the binomial denominator did. This has been fixed.

xtpcse with the options **correlation(ar1)** or **correlation(psar1)** was reporting an
uncentered R-squared -- an R-squared with a base of 0 rather than the mean
of the dependent variable -- and associated model sum of squares **e(mss)** and
model degrees of freedom **e(df_m)**. It now computes a centered R-squared
unless option **noconstant** is specified.

----- **update 25oct2000** --------------------------------------------------------

stsplit, as updated 19sep2000, when used with datasets containing more than
32,766 observations, would fail to split the data correctly. This has been
fixed.

----- **update 12oct2000** --------------------------------------------------------

stcurv, with multiple failure data and used after **streg,** **dist(lognormal)**,
produced a graph with a jagged line; this has been fixed. In addition,
**stcurv** used after **streg,** **dist(exponential)** had a spelling error on the
default labeling of the axis.

vif on rare occasions would fail to compute variance inflation factors for all
the rhs variables in the model.

----- **update 19sep2000** --------------------------------------------------------

On-line help and search index brought up to date for STB-57

bstat has a new option **title()** allowing the title on the output to be changed.

stcox did not save in **e()** the names of the variables created when the
**basehazard()**, **basechazard()**, or **basesurv()** options were specified and fully
spelled out rather than entered as abbreviations, such as **baseh()**, **basec()**,
and **bases()**. This caused no problems whatsoever, but could cause problems
if you wanted to use the saved results.

stcurv's new **outfile(***filename***)** option will save the data generated to produce
the graphed curves in a Stata .dta dataset for later use.

stsplit has been improved. It runs faster, it has additional options, and it
has a new syntax that facilitates splitting at failure times. See help
stsplit. In addition, the new help file stsplit2 is very much like a FAQ
in that it explains the usefulness of splitting at failure times and the
relationship between stcox's **exactp** option and conditional logistic
regression estimates produced by clogit; see help stsplit2. There were no
bugs in the previous **stsplit**.

----- **update 11sep2000** --------------------------------------------------------

alpha with option **generate()** would fail with an "invalid syntax" error message
if the option was completely spelled out; this is fixed.

avplot after regress with the **cluster()** option would title the resulting plot
using the non-robust standard error.

xtgee on rare occasions would fail with error message r(505) "matrix not
symmetric". This has been fixed.

----- **update 18aug2000** --------------------------------------------------------

tabstat has a new **statistics(sdmean)** option to produce standard deviation of
the mean, the **statistics()** option is now case insensitive, and the default
output format has been changed if only one variable is specified.

----- **update 15aug2000** --------------------------------------------------------

**Stata executable**(*), all platforms.

rotate with the **varimax** option, used after factor with two factors retained,
produced incorrect answers; results are now correct.

----- **update 14aug2000** --------------------------------------------------------

dprobit would give an error message if any of the independent variables
contained the string "_cons" in the variable name.

xtpcse with the option **correlation(ar1)** or **correlation(psar1)** now constrains
estimates of panel-level autocorrelation to be in the range [-1,1]. This
bounding imposes the theoretical limits on the correlations and allows the
Prais-Winsten computation to always be performed. The change only affects
estimation results for unusual datasets where any estimated panel-level
autocorrelation fell outside the range [-1,1]. Even in these cases, the
new results are asymptotically equivalent to the prior results.

----- **update 02aug2000** --------------------------------------------------------

avplot after regress with the **robust** option would title the resulting plot
using the non-robust standard error.

dfuller reported an incorrect 1% critical value when the number of observations
was between 101 and 500 and options **trend** and **noconstant** were not
specified.

pperron reported incorrect Z(t) and Z(rho) statistics. In addition, as with
**dfuller**, **pperron** reported incorrect 1% critical values when the number of
observations was between 101 and 500 and options **trend** and **noconstant** were
not specified.

----- **update 17jul2000** --------------------------------------------------------

On-line help and search index brought up to date for STB-56

----- **update 07jul2000** --------------------------------------------------------

xtpcse when specified with the **pairwise** option would exit with a "matrix not
positive definite" message in the unusual case when the estimated
covariance matrix of the disturbances was not positive definite. The error
message has been improved to state that the pairwise option may not be
used. As noted in help xtpcse, this can only occur when the **pairwise**
option is specified.

strate with option **smr** and option **output()** would fail with an error message.
It now works.

stsum with option **by()**, and when two variables were specified in the **by()**,
would sometimes display the stub of the table with quote characters in odd
positions. This is fixed.

----- **update 03jul2000** --------------------------------------------------------

stset, due to a recent update, when **exit(***eventvar***==***numlist* **time** *varname***)** was
specified, could ignore the events in favor of the time, treating the
option as if **exit(time** *varname***)** had been specified. The same could happen
with the **enter()** and **origin()** options. The problem could only occur when
both an event list and a time were specified; there was no problem with
statements such as **exit(***eventvar***==***numlist***)** or **exit(time** *varname***)**.

----- **update 29jun2000** --------------------------------------------------------

ml has improved convergence properties for pathological likelihoods where one
or more parameters are being driven to positive or negative infinity.

reshape, in a certain case, gave an unhelpful error message. The error message
has been improved.

sts **generate**, in rare circumstances, would give an error message rather than
producing the requested result. That is fixed.

tabstat is a new command to display a table of summary statistics; see help
tabstat.

xi would give an error message if one or more of the variables in the model
contained a constant; **xi** should have not complained and simply allowed the
model to be estimated. This arose as a side effect of the 12jun2000 update
and is now fixed.

----- **update 26jun2000** --------------------------------------------------------

wntestb had an unnecessary global macro that was never explicitly used but
could on occasion be outputted on the graph's title. This has been fixed.

xthaus when used with no covariates which vary within panel would produce a
syntax error. It now gives a more informative error message.

xtpcse specified with options **correlation(ar1)** and **pairwise**, and when there
were no observations on which to compute the autocorrelation parameter,
would exit with the error message "matrix has missing values". It now
exits with the appropriate error message "insufficient observations".

----- **update 12jun2000** --------------------------------------------------------

collapse would not allow a mix of its two syntaxes, one of which specified the
name of the new variable and the other of which did not, such as "**collapse**
**newvar1=oldvar1 oldvar2 newvar3=oldvar3**". "**collapse newvar1=oldvar1**
**newvar3=oldvar3**" was allowed as was "**collapse oldvar2**", but you could not
mix the two together into one statement. Now you can.

xi would give a syntax error if what followed it contained a reference to a
Stata function. This was fixed on 31may2000, but not completely.

----- **update 31may2000** --------------------------------------------------------

dstdize now saves numbers of observations, unadjusted, and adjusted rates for
use by other programs; see help dstdize for details.

xi would give a syntax error if what followed it contained a reference to a
Stata function. This has been fixed.

----- **update 25may2000** --------------------------------------------------------

**Stata executable**(*), all platforms.

xtclog produced estimates of the parameters and standard errors that were only
accurate to a few digits or, in a few cases, failed to converge. This was
traced to an error in the calculation of the matrix of 2nd derivatives and
is fixed.

----- **update 24may2000** --------------------------------------------------------

ci with the options **poisson** and **by()** along with an **if** restriction would fail to
produce results when one of the by groups had no observations meeting the
if condition.

hausman output makes it clearer that the more efficient model in the test must
be fully efficient.

----- **update 08may2000** --------------------------------------------------------

On-line help and search index brought up to date for STB-55

----- **update 19apr2000** --------------------------------------------------------

codebook would produce an error when sent certain variable names such as **_d**.
This has been fixed.

fracpred with the **dresid** option and fracplot gave uninformative error messages
after "**fracpoly clogit** ..." or "**fracpoly probit** ..." They now produce more
informative errors. (The manual does not list **fracpoly** as working with
clogit and probit, but it does. Neither **clogit** nor **probit**, however, can
produce deviance residuals and so **fracplot** and **fracpred, dresid** are not
allowed after **fracpoly** with either of these commands.)

gladder now works with variables with nonpositive values.

nl now includes an **if** exp on an "**nl ?**" call. See "Advanced programming of
nlfcns" in help nl. On a query call, the syntax is now

**nlfcn** **?** [*varlist*] **if** *exp* [**,** *options*]

This allows the nlfcn to perform initialization computations restricted to
the relevant subsample within the portion of the code that sets the initial
parameters into global macros. In addition, **nl** will no longer remove
existing variables with the same name (or similar name based on
abbreviation rules) as the parameter names. The **leave** option is still
supported, but a check is first made that no existing variables by those
names exist before creating the variables.

predict after stcox and **cox** reported hazard ratios of 1 rather than exp(x*b)
whenever x*b>18. This has been fixed.

qladder is a new command that displays the quantiles of transforms of varname
according to the ladder of powers against the quantiles of a normal
distribution.

snapspan with the **generate(***newt0var***)** option now formats *newt0var* to have the
same format as the *timevar*.

svyolog, svyoprob, and svymlog produced uninformative error messages when there
were more than 50 outcomes (a Stata limit). It now produces the
appropriate error message and return code r(149).

xtpcse now allows the time variable to be used as a regressor with any set of
options. Previously, **xtpcse** refused to estimate models with the time
variable as a regressor when options **correlation(ar1)** or **correlation(psar1)**
were specified.

----- **update 17apr2000** --------------------------------------------------------

**Stata executable**(*), all platforms.

display's **_request()** option now allows more than 80 characters of input.

format **_all** caused a crash if there were no data in memory; that is fixed.

matrix **accum** now produces an error when _N==1.

matrix **glsaccum** now produces correct results when used with time-series
operators, and when the **rows()** option is used to repeat rows of the
weighting matrix. In addition, **matrix** **glsaccum** now produces an error
message when the data are not sorted by group and when the weighting matrix
in nonsymmetric.

matrix **vecaccum** with time-series operators now correctly labels the rows.

Power calculations a^b are now calculated by repeated multiplication for
integer values of b<=32; previously b<=4 was used. This makes results more
accurate.

In matrix expressions, the **nullmat()** function worked only on the left hand side
of the comma and backslash operators; it now works on both the left and
right hand sides.

**Stata executable**(*), Unix.

Under Solaris, the message "operating system refuses to spawn new process"
should no longer appear when you attempt an ls or shell command.

Under Red Hat 6.2, some people reported that Stata crashed when invoked, before
the initial prompt. That is now fixed.

----- **update 05apr2000** --------------------------------------------------------

xtgls with options **corr(ar1)** or **corr(psar1)** did not fully honor the **force**
option and this could lead to the error r(504) "matrix has missing values".
**xtgls** now always honors the **force** option.

xtpcse now allows estimation when the panel-level autocorrelation parameter,
rho_i, cannot be computed for one or more panels and the option
**correlation(psar1)** has been specified. Previously, **xtpcse** would return the
error message r(504) "matrix has missing values" and refuse to estimate the
model; it now assumes that these correlations are 0 and proceeds with the
estimation.

----- **update 27mar2000** --------------------------------------------------------

sts **list** with the **by()** option used an incorrect display format when the
by-variable was numeric. Although the output was correct, the most
appropriate display format was not always used.

svytab produced an "operator invalid"; r(198) error message when there were
value labels containing a period. This has been fixed.

----- **update 24mar2000** --------------------------------------------------------

intreg now handles aweights differently; see comment concerning 20mar2000
update to **tobit** and **cnreg** below.

kwallis was updated 09mar2000 to report an adjusted-for-ties chi-squared
statistic. This new statistic was calculated incorrectly when there were
missing values.

xtclog, xtlogit, xtnbreg, xtpois, xtprobit, and xtreg, all with the **pa** option,
no longer allow aweights. With **pa**, however, they all now allow fweights.
All now work with the **noconstant** option.

xtgee has had numerous changes made to it. These include

1. The default divisor for computing correlations and standard errors has
been changed from 1/(N-p) to 1/N. New option **nmp** will produce the
previous results. (Which divisor is used is of little importance since
both are asymptotically correct. 1/N has the slight advantage in that
it scales; see help xtgee.

2. In the particular case of **family(gaussian)**, the default normalization
for calculating the robust VCE is now n/(n-1) instead of
[n/(n-1)]*[(N-1)/(N-p)], where n = # of panels and N = # of
observations, and this change was made for the same reasons as (1).
New option **rgf** will reproduce the previous results.

3. The calculation of the working correlation matrix, and thus the
resulting estimates, in the case of unbalanced panels with
**corr(nonstationary)** or **corr(unstructured)**, has been changed.

4. **xtgee** no longer allows aweights.

5. **xtgee** now allows fweights.

6. The way **xtgee** calculates weighted results has changed.

See http://www.stata.com/support/faqs/stat/xtgeetech.html for a technical
FAQ on this.

For these changes to take effect, you must also install the 20mar2000
executable update.

----- **update 20mar2000** --------------------------------------------------------

**Stata executable**(*), all platforms.

clogit with no right-hand-side variables reported an obviously incorrect
log-likelihood value when there was more than one failure per group. In
addition, **clogit** with the **offset()** option reported an incorrect model
chi-squared statistic.

Matrix function **det()** was reported to return a 0 for the determinant when the
matrix had zeros on the diagonal; that is fixed.

mlogit's convergence has been improved; it now converges for some models where
previously it did not. (This resulted from improving the way stepping is
handled in the internal optimizer and should improve convergence of all
models).

tobit and cnreg now handle aweights differently. Previously, they were just
scaled and applied to the likelihood function in the "ordinary" way, but
that solves no real-world problem. Now they are applied in the correct way
to deal with cell-mean data with these two likelihood functions.

(**aweight**s have been going through a change for many releases now. They
started as being defined as rescaled **fweight**s, perhaps useful, and perhaps
not, and most estimators allowed them. Later, **aweight**s, still defined in
this mechanical way, were deleted from estimators in which they solved no
real-world problem. By that logic, **aweight**s should have been deleted from
**tobit** and **cnreg**. **aweight**s are now in the process of being given a
different definition: that of producing estimates when the estimator is
applied to cell-mean data, even if this requires changing the mechanical
definition. The mechanical definition arose because it was the solution to
handling cell-mean data in linear regression.)

tobit and cnreg now produce better starting values and so should converge more
quickly. There was previously one report of a model in which **tobit** refused
to converge; the new starting values fix that.

Internal changes were made to support the 24mar2000 update to xtgee, listed
above.

**Stata executable**(*), Unix.

Stata would refuse to execute from a Gnome terminal under Red Hat Linux 6.1.
That is fixed.

----- **update 13mar2000** --------------------------------------------------------

egen's **robs()** function with the **strok** option (introduced 16Aug1999) counted the
number of missing instead of the number of non-missing observations. This
has been fixed.

On-line help and search index brought up to date for STB-54

----- **update 09mar2000** --------------------------------------------------------

biprobit has been improved in three ways. (1) **biprobit** did not respect the **ml**
options; this has been fixed. (2) predict after **biprobit** defaulted to
**pmarg1** when, per the documentation, it should have defaulted to **p11**. (3)
**biprobit** with **partial** option would report incorrect values for the
comparison test of rho=0.

cttost would fail if an enter variable was specified to indicate delayed entry.

heckman has four new options for use when option **twostep** is specified:
**rhosigma**, **rhotrunc**, **rholimited**, and **rhoforce**. These options affect the
handling of estimates of rho outside the bounds [-1,1] and are relevant
only with the two-step method because obtaining values outside those bounds
is not possible using maximum likelihood. In addition to help heckman, see
http://www.stata.com/support/faqs/stat/twosteprho.html for technical
details.

kwallis now reports both the unadjusted and the adjusted-for-ties chi-squared
statistics and associated p-values.

strate when used with the **output()** option would save the person-time values in
a string rather than numeric variable. This has been fixed.

stset with the **time0(***varname***)** option correctly did not use observations with
missing values of *varname*, but incorrectly did not use such observations
even when processing the **entry(***eventvar***==***numlist***)** option. A missing value
of **time0()** for the first observation on a subject is reasonable and even
so, that record should be able to trigger entry-into-the analysis because
it is the data on the subsequent record (for which **time0()** is not missing)
that is relevant.

----- **update 21feb2000** --------------------------------------------------------

heckman with the **twostep** option, and only with the **twostep** option, produced
incorrect standard errors (they were overly conservative) and incorrect
estimate of rho (it was attenuated toward zero) when all (emphasis on all)
the independent variables in the regression equation were nonmissing in any
observation flagged as not observed.

table with the **replace** option would give an error message if a variable named
**table1** was already defined in the dataset.

webseek under Windows and Mac did not honor the **results** option.

----- **update 09feb2000** --------------------------------------------------------

gamma, gompertz, llogist and lnormal parametric survival regression models,
when used outside the **st** system, would fail if the failure-event variable
was not coded 0/1. This has been fixed. These programs assume that the
failure-event variable is 0 if the observation is censored and a value
other than 0 -- typically 1 -- if the observation represents a failure.

kap now reports and saves in **r(se)** the standard error for the estimated kappa
statistic. Also, the output table now uses a better display format for the
outcome value when **kap** is used with more than two raters and a non-integer
scale.

stset without arguments and streset failed to reset the data properly if
**failure(***varname***==***numlist***)** was originally specified, for example
**failure(event==12 13 14)**. In addition, the text of an
observation-exclusion message was changed from "obs begin on or after
enter" to "obs begin on or after exit" or "obs begin on or after first
failure", as appropriate. Only the text of the message was changed.

xtgls now returns the more appropriate error code 459 rather than 498 when the
data do not meet the requirements of the estimator.

xthaus now refuses to perform the Hausman test and suggests use of the command
hausman when the estimate of sigma_u (the estimate of the variance of the
random effect) is 0. The random-effects estimator in this case has
degenerated to pooled OLS and the difference of the variance-covariance
matrices computed by **xthaus** may no longer be positive definite. The test
statistics reported by the more general **hausman** command are preferred when
the difference matrix is not positive definite.

----- **update 28jan2000** --------------------------------------------------------

webseek is a new command to perform a keyword search of user-written additions
to Stata. **webseek** searches not only the STB but the entire web, including
user sites.

----- **update 27jan2000** --------------------------------------------------------

arch, heckman and intreg now check for collinearity between the dependent and
independent variables. If collinearity exists, an error message explaining
which variables are collinear is displayed.

stcurv now accepts multiple **at(***varname***=***#* ...**)** options, called **at1()**, **at2()**,
..., **at10()**. This allows multiple curves to be plotted on the same graph.

----- **update 21jan2000** --------------------------------------------------------

**Stata executable**(*), all platforms.

Stata can now allocate up to 16,384 gigabytes of memory if the hardware
supports it. (With the exception of the 64-bit DEC Alpha, most hardware
can support only 4 gigabytes.)

There is a new **-m** (Unix) **/m** (Windows) start up option that works like **-k**
(**/k**) except that memory is specified in megabytes, not kilobytes.

Stata misparsed expressions with a very unusual set of characteristics, for
example "**(substr(`"a"bc"',1,1)=="f")|(1)**" and similar expressions that had
(1) open and close parentheses at the beginning and end, (2) the
parenthesis did not match, (3) a function was used inside the parentheses,
and (4) the expression contained both simple and compound double quotes.
This has been fixed.

graph**,** **c(L)** mistakenly connected points when values of x[_n-1]>x[_n] but the
values were exceedingly close. This has been fixed.

matrix and scalar will no longer create matrices and scalars with the reserved
names **_pred**, **_b**, **_n**, **_N**, **float**, **double**, **int**, **long**, **_uniform**, **_coef**, **_rc**,
**_pi**, and **byte**.

matrix *name* **=** *exp* could sometimes report an "expression too long" error when
the expression was not too long, depending on the expressions previously
executed (technically, **matrix** did not clear the literal stack). This has
been fixed.

predict**, residual** after **regress, robust** now produces correct results when the
dependent variable contains time-series operators.

**Stata executable**(*), Windows 3.1:
dir had a y2k bug and reported two-digit years for the file date and
reported "100" for files dated 2000. This has been fixed.

**Stata executable**(*), Windows 2000/98/95/NT:
On the print log, the radio button for printing a selection is now disabled
as it always should have been.

**Stata executable**(*), Windows 2000/98/95/NT and Unix:
Do-files with Mac end-of-line characters (carriage return only) can now be
executed without translation.

----- **update 19jan2000** --------------------------------------------------------

areg and xtreg with the **fe**, **be**, and **re** options (**xtreg** without **mle**) now produce
more accurate results. For most datasets, this improvement changes
coefficient estimates in the 9th or 10th decimal place.

Internally, all of these estimators work by transforming the data into
differences from group means, pseudo differences from group means, or the
group means themselves. Previously, the transformed data was calculated in
double precision but stored in float precision unless the original variable
was double. Now transformed results are stored in double precision in all
cases.

xtdata has new option **nodouble**. **xtdata**'s default behavior has been changed so
that the transformed variables are recast to double, making results
slightly more precise. Option **nodouble** restores the previous behavior.

----- **update 14jan2000** --------------------------------------------------------

arch now computes, in all cases, the model chi-square test using all
coefficients entering the specification of the conditional mean.
Previously, in the specific case where option **archm** was specified with
options **ar()** or **ma()** and no independent variable list was specified, the
**ar()** and/or **ma()** terms were excluded from the test.

areg now saves the adjusted R-square in **e(ar2)**.

prtesti has new option **count**. **count** specifies that counts rather than
proportions are specified. For example, "**prtesti 20 .2 30 .3**" tests
whether an observed proportion of .2 in 20 observations could be from the
same population and an observed proportion of .3 in 30 observations.
"**prtesti 20 4 30 9, count**" performs the same test but the observed
frequencies are specified as counts.

xtgls previously implemented a generalization of PCSEs that allowed users too
easily to request covariance structures that are NOT what most people
currently mean by PCSE. This would occur if **panels(heteroskedastic)**,
**panels(independent)**, or no **panels()** option was specified.

Now **xtgls**, when specified with options **pcse** or **ols**, invokes the new command
xtpcse to perform OLS and Prais-Winsten regressions with panel corrected
standard errors (PCSE).

If options **ols** or **pcse** are specified and the requested covariance structure
is not **panels(correlated)**, **xtgls** will now display an error message.
**xtgls**'s previous behavior can be obtained by specifying the option
**forcepcse**.

**xtgls** has also been modified to return the estimated disturbance **e(Sigma)**
that was used in computing the coefficient and variance estimates and to
use this estimate in computing the log likelihood. Previously, if the
option **twostep** was specified, **xtgls** returned an estimate of Sigma based on
the FGLS coefficient estimates. The two estimates of Sigma are
asymptotically equivalent. The numerical accuracy of xtgls has also been
improved when **corr(ar1)** or **corr(psar1)** are specified.

xtpcse is a new command to more accurately reflect the use of the term PCSE in
the literature. In addition to providing the functionality of **xtgls, ols**
and **xtgls, pcse**, **xtpcse** allows for unbalanced panels, estimation of
autocorrelation parameters when there are gaps in the time series, and the
use of time-series operators.

----- **update 13jan2000** --------------------------------------------------------

On-line help and search index brought up to date for STB-53.

----- **update 03jan2000** --------------------------------------------------------

ivreg now produces a better error message when the equal sign is not specified
to separate the instrumented variables from the instrument list.

xtgls's help now clearly documents how parameter estimates are computed when
options **pcse** or **ols** are combined with a specification for autocorrelation
-- option **corr(ar1)** or **corr(psar1)**.

predict after reg3 when the **residual** option is specified and more than one
equation has the same dependent variable, now computes residuals properly.
Previously, in this unusual event, the negative of the Xb prediction was
returned instead of the residual.

----- **update 22dec1999** --------------------------------------------------------

biprobit now identifies collinearity among variables and its error messages
have been improved.

collapse's **sum** and **rawsum** statistics now compute all sums in double precision.
Previously sums were calculated in double precision only if the original
variable was of type long or double.

**collapse** now also allows spaces between the parentheses and the statistic
name. For example, before you had to type "**collapse (mean) x**", now you can
type "**collapse ( mean ) x**".

for incorrectly limited the number of concurrent lists to 8 instead of 9. This
has been fixed.

hausman could not perform the test when one estimator used equation names and
the other did not. New option **equations()** solves this problem; see help
hausman.

tsfill with the **full** option could on occasion produce entries within a panel
with incorrect time values resulting in two entries with the same time
value and another time value absent. This has been corrected.

----- **update 17dec1999** --------------------------------------------------------

prtesti reset the default confidence level for confidence intervals if you
specified its **level()** option, meaning all subsequent commands showed
confidence intervals of that level until you "**set level 95**" again. **prtesti**
no longer does that.

stset's **origin(***varname***=***#s***)**, **enter(***varname***=***#s***)**, and **exit(***varname***=***#s***)** options,
did not work unless varname was the same as the failure variable. E.g.,
"**failure(outcome==5) exit(outcome==3)**" did work but "**failure(outcome==5)**
**exit(diag2==32)**" did not. This is fixed.

----- **update 06dec1999** --------------------------------------------------------

heckman and heckprob, if the dependent variable was abbreviated, used the
abbreviated name on the output (as well as to label the saved results **e(b)**
and **e(V)**).

kdensity, when **aweight**s were specified, would mistakenly report "... real
changes made".

strate would distort the table alignment when reporting large values.

tabodds produced an ambiguous error message when *case_var* was not numeric. The
error message has been changed.

ttest and sdtest, when used with **by()**, and in particular when the by-variable
had a variable label containing parentheses, quotation marks, etc., would
fail with an uninformative error message.

----- **update 30nov1999** --------------------------------------------------------

ivreg now saves in **e(insts)** the full list of exogenous variables rather than an
abbreviated list containing the first few exogenous variables followed by
an ellipse (...).

prtesti with **level(***#***)** option would incorrectly produce an error message; this
has been fixed.

----- **update 22nov1999** --------------------------------------------------------

arch's **predict** will now produce predictions for ARCH models with ARCH-family
terms and with multiplicative heteroskedasticity. Previously, **predict**
refused to produce predictions for these models. **predict** will also now
handle lags and other operated forms of the dependent variable in the
multiplicative heteroskedastic component, that is, when the original model
was estimated with **arch**'s **het()** option.

dprobit now names the columns of the saved matrices **e(dfdx)** and **e(se_dfdx)** with
the variable names from the estimated model.

heckprob with **nolog** option would incorrectly produce an "unrecognized command:
nolog" error message; this has been fixed.

logistic has new option **coef** which causes **logistic** to report the estimated
coefficients rather than the odds ratios (exponentiated coefficients).

sts **graph** with option **enter** and not **lost**, would not report the number who enter
and the number censored on the graph; you had to specify both the **enter** and
**lost** options. Now **enter** implies **lost**.

xtgls now uses a default maximum iterations of 16,000 when option **igls** is
specified.

----- **update 17nov1999** --------------------------------------------------------

cs's **by()** option has been enhanced to take more than one stratification
variable.

stdes with the **weight** option would incorrectly produce an "invalid syntax"
error message; this has been fixed.

svytab with only one row or column would produce an error "name conflict";
r(507). This has been fixed.

svytotal, svymean, and svyratio produced an "operator invalid"; r(198) error
message when the **by()** option variable had value labels that contained a
period. This has been fixed.

xtgee will now estimate models with options **binomial** and **link(logit)** or
**link(cloglog)** when the model contains a perfect predictor for some of the
observations. Previously, **xtgee** would refuse to estimate such models and
report "Unable to identify sample".

xtgls now estimates models if option **corr(ar1)** is specified and the
autocorrelation is indeterminate for one or more panels. Prior to this
update **xtgls** refused to estimate such models.

----- **update 12nov1999** --------------------------------------------------------

On-line help and search index brought up to date for STB-52.

----- **update 05nov1999** --------------------------------------------------------

**whatsnew** (this file) improperly described the 4nov1999 update made to table.
The wording below is fixed.

----- **update 04nov1999** --------------------------------------------------------

bsample with the **cluster()** option did not produce a bootstrapped sample if the
data were not sorted by the cluster variable. This is now corrected. The
problem did not affect bs or bstrap because they called **bsample** after
sorting on the cluster variable.

egen's **count()** function now allows string as well as numeric expressions. In
the case of **count(***exp***)** where *exp* is a string, observations in which *exp*
evaluates to "" are considered to be missing.

ksm with the **weight** option would incorrectly produce an "invalid syntax" error
message; this has been fixed.

separate objected to the use of quotes in its **by()** option, such as "**separate**
**make, by(make=="Subaru")**". This is fixed.

stset: the text of an informatory message was changed.

table displayed strange (temporary) variable names in the heading if five
statistics were requested and the variables had long names. Variable names
are now shortened (truncated) in the heading.

xtcorr has new option **compact** that displays only the estimated parameters
(alpha) of the matrix of within-group correlations rather than the entire
matrix.

----- **update 15oct1999** --------------------------------------------------------

kdensity now correctly reports the number of observations used when the number
specified in **n()** is larger than the total sample size. Also, when
specifying **at()** with tied values, **kdensity** now retains the original order
of the dataset. Additionally, **kdensity** now runs faster.

qnorm no longer produces an error when the **connect()** or **symbol()** graph options
are specified.

_rmdcoll is a new programmer's command that identifies and removes collinearity
from variable lists. See help _rmdcoll.

svytab with the **subpop()** and **obs** options now displays subpopulation counts in
each cell rather than the full population counts previously displayed.

----- **update 12oct1999** --------------------------------------------------------

**Stata executable**(*), all platforms.

Stata has had a long history (since Stata 1.0) of confusing expressions such as
e+3 with numbers such as 1e+3, leading to syntax errors and users avoiding
the name e for variables or scalars. That has been fixed.

anova with aweights now works. The precision improvements made to **anova** on
2aug1999 resulted in aweighted models being reported with all zero
coefficients and missing test statistics. That has been fixed.

arima, or rather, "**predict, dynamic()**" used after "**arima, ar(1)**" now produces
dynamic predictions. Previously "**predict, dynamic()**" after "**arima, ar(1)**"
produced structural predictions. The problem existed only with pure AR(1)
models -- "**predict, dynamic()**" used after "**arima, ar(1) ma(1)**", for
instance, always produced dynamic predictions. Now all produce dynamic
predictions.

cnreg now saves **e(censored)** containing the censoring variable name along with
the other saved results.

estimates **matrix** and return **matrix** will no longer create multiple matrices with
the same name. Instead, the previous matrix is erased and the new matrix
replaces it. This problem only caused a waste of memory.

infile and infix no longer issue an error message when the **using()** option is
specified and the (irrelevant) data file mentioned in the dictionary (if
any) does not exist.

insheet will no longer allow creation of str81 variables.

ivreg now produces more digits of precision when used with ill-conditioned
data.

macro **drop** now allows multiple wildcard references such as "**macro drop A* B***".

table now honors specified formats wider than 9 characters.

tobit now saves **e(llopt)** and **e(ulopt)** -- the lower and upper bounds -- along
with the other saved results.

**Stata executable**(*), Unix.

Stata for Unix is now 8-bit cleaner. Stata now defaults to specifying -e
("stata -e") when loading the pipeline driver (pd) automatically. This
allows 8-bit streams to be sent to the terminal.

----- **update 28sep1999** --------------------------------------------------------

On-line help and search index brought up to date for STB-51.

joinby has been made faster and some new options were added. There were no
problems with the previous **joinby**.

qreg, iqreg, sqreg, and bsqreg sometimes reported that a collinear variable was
being dropped whereas in actuality another of the collinear variables was
dropped. The reported variable dropped now always agrees with the actual
variable dropped. In rare instances, this could lead to a "conformability
error" when using **bsqreg**; this no longer occurs.

pwcorr stopped with an error message if a pair of variables had no observations
in common; now **pwcorr** reports missing value for the correlation.

_rmcoll is now documented on-line. This is an advanced programming command for
use in writing estimation commands that are to run efficiently.

xttab produced an inappropriate error message when run on zero observations.

----- **update 10sep1999** --------------------------------------------------------

cloglog with **fweight**s reported incorrect number of zeros and ones. The
estimation results were correct. This has been fixed.

dotplot now accepts a string variable in the **by()** option.

quadchk now works correctly after xttobit. **xttobit** now saves returned results
**e(ulopt)** and **e(llopt)** for use by **quadchk** but which other programs may now
use. **e(ulopt)** and **e(llopt)** are the **ul()** and **ll()** options specified by the
user.

recast has a new **force** option that forces the change to be made even if that
change would cause a loss of precision, introduction of missing values,
etc.

reshape now allows variable-name abbreviation for varlist and **j()** option when
changing data from long to wide form.

reg3 and sureg with weights specified now save the weighting expression in
**e(wexp)** and the weight type in **e(wtype)**.

zinb option **nbreg** has been replaced by option **vuong**. **vuong** requests that a
Vuong test of ZINB vs. negative binomial be done.

zip option **poisson** has been replaced by option **vuong**. **vuong** requests that a
Vuong test of ZIP vs. Poisson be done.

----- **update 30aug1999** --------------------------------------------------------

xi, when producing interactions of variables taking on hundreds of different
values, could fail with the error message "syserr: length |5| not right";
r(198). This has been fixed.

----- **update 27aug1999** --------------------------------------------------------

cchart and pchart now correctly plot and report the number of units out of
control if the lower control limit is zero or lower.

predict after streg, **dist(exponential)** and **streg**, **dist(weibull)** now calculates
predicted time without including Euler's constant.

predict after streg, **dist(gamma)** now produces correct predicted time values
when kappa is negative. Also the way it calculates hazard values has been
made more numerically stable.

recode, when used on a variable of storage type long or double, and the
variable contained lots of significant digits, could incorrectly include in
recode ranges values that should have been excluded. This has been fixed.

sts **generate** *newvar* **= s** now produces survival probabilities equal to 1 rather
than missing when there are no failures in the data.

tsset now returns values for the time unit (that is, periodicity) and the
time-series format. **r(unit)** contains **daily**, **weekly**, **quarterly**, etc.
**r(unit1)** contains **d**, **w**, **q**, etc. **r(tsfmt)** contains the time-series format.

----- **update 17aug1999** --------------------------------------------------------

codebook now handles date variables more elegantly. In addition, the new
option **notes** displays notes associated with variables and the new option
**header** reports the dataset's name, etc., above the report on the individual
variables. New option **all** is equivalent to specifying both **header** and
**notes**.

xi now works properly with commands that use bound (parenthesized) equation or
variable lists (such as ivreg) and with commands that take equations or
variable lists in options (such as heckman).

----- **update 16aug1999** --------------------------------------------------------

arima with the **arima()** option specified as **arima(***k***,0,0)** now estimates ARIMA
models with *k* AR terms and no MA terms; previously **arima(***k***,0,0)** was
incorrectly taken to mean *k* AR and *k* MA terms.

egen's **robs()** function has a new **strok** option. **strok** allows string variables
to be specified and they are counted as containing missing when the string
variables contain "".

streg**, dist(exponential)** and ereg, when the **robust** option is specified, now
label the chi-squared model test "Wald chi2". They previously incorrectly
labeled the test "LR chi2".

svytab can now tabulate variables whose variable labels contain quotes.

----- **update 05aug1999** --------------------------------------------------------

lrecomp is a new command for making tables of number of correctly estimated
digits (LREs) when comparing calculated results to known-to-be-correct
results.

----- **update 02aug1999** --------------------------------------------------------

**Stata executable**(*), all platforms.

anova now provides more digits of precision when used with ill-conditioned
data.

mlogit, ologit, and oprobit now produce correct standard errors when
**pweight**s are specified with option **cluster()**. Previously, absurdly large
standard errors were reported.

net now works with paths including "**..**" for all HTTP servers, including Mac
servers. Previously, **net** relied on the server to handle relative paths.

regress now provides more digits of precision in R-squared near 1
regressions.

Typing "**save, replace**" now works when the remembered filename exceeds 64
characters.

The **subinstr** extended macro function with the option **word** now correctly
handles words at the beginning of a string when the first character is
doubled.

table now handles spaces at the beginning and end of string variables more
elegantly.

tab2 now allows option **exact** to be abbreviated **e** as per the documentation.

**Stata for Windows executable**(*).

The do-file editor now includes **.dct** files in the list of editable files.

The log window now remembers the printer font as well as the screen font
between sessions.

Copying and pasting into the data editor no longer creates a row of missing
values below the pasted data.

Stata now reports attempts to open log files in read-only directories.

**Stata for Mac executable**(*).

Copying and pasting into the data editor no longer creates a row of missing
values below the pasted data.

----- **update 29jul1999** --------------------------------------------------------

On-line help and search index brought up to date for STB-50.

sts **graph** now includes option **censored()** which allows placing tick marks on the
graph to indicate censorings.

----- **update 23jul1999** --------------------------------------------------------

dprobit added two matrices to saved results -- **e(dfdx)** records the vector
marginal effects and **e(se_dfdx)** records their standard errors.

cc now suppresses the test for homogeneity when any of the estimated odds
ratios are zero or missing.

reshape. A message **reshape** sometimes displays has been reworded to correct a
typographical error.

----- **update 13jul1999** --------------------------------------------------------

aorder now handles multiple number fields within variable names.

centile now correctly handles the case of no observations (it previously went
into an endless loop) and it correctly handles **if** *exp* and **in** *range* when
there are multiple variables.

cf could become confused when different variables appeared in both datasets and
the name of one of the variables could be interpreted as an abbreviation of
the other.

dotplot now recognizes labels for the y variable.

egen's **rmean()** and **rsum()** functions now allow one or more variables rather than
requiring at least two.

nl has a new **delta(***#***)** option and a default value for same that should improve
the accuracy of coefficients and standard-error estimates.

predict after streg**, dist(gamma)** produced incorrect hazard values. This also
caused stcurv to make incorrect plots.

heckman with the **twostep** option sometimes reported the message "matrix not
symmetric".

ksmirnov, after reporting an uncorrected P-value of zero, reported the
corrected P-value as zero rather than missing.

mhodds now displays better headers when option **by()** is specified with string
variables.

streset would fail if the **before** option was specified.

xtnbreg now honors the **nolog** option.

----- **update 28jun1999** --------------------------------------------------------

arima sometimes produced unclear and misleading messages during optimization.
Messages have been reworded.

cf's option **verbose** did nothing; it is fixed.

collapse no longer retains the name of the original dataset and so typing
"**save, replace**" after **collapse** will not replace the original, uncollapsed
data.

compare run on some files that contained string variables presented a syntax
error and stopped; that is fixed.

corrgram, ac, and pac have been given minor improvements: **corrgram** now stores
results in **r()**, **ac** is faster, and **pac** handles errors better.

fracpoly. Setting the random-number seed did not re-create an analysis when
the **add** option was specified.

lsens's **replace** option did not work; it now does.

stsplit and stjoin. **stsplit**'s way of recording time could cause **stjoin**, in
some cases, not to be able to rejoin all the records possible.

svytab with the **subpop()** option mistakenly printed the word "dash" in its
header; it no longer does.

----- **update 22jun1999** --------------------------------------------------------

**Stata executable**(*), all platforms.
HTTP proxy authorization has been added.

In processing numlists, Stata issued an error when numlists of the form
"*#***(***#***)***#*" or "*# #* **to** *#*" did not start with an integer element.

The numlist parsing command issued an out-of-range error when option
**range(<***#***)** was specified even when the list did not contain out-of-range
elements.

summarize now saves **r(sd)** = sqrt(**r(Var)**).

tabulate truncated a character in the labels of one-way tabulations when
the labels were longer than 8 or 9 characters.

**Stata for Windows executable**(*).
**--more--** conditions now work as expected with dialog boxes.

The do-file editor now clears the edited filename when a new instance is
started. Thus, restarting the do-file editor and clicking the save button
now results in the do-file editor asking for the name under which the file
is to be saved.

----- **update 31may1999** --------------------------------------------------------

On-line help and search index brought up to date for STB-49.

cloglog with the **noconstant** option sometimes dropped variables when it should
not have. That has been fixed and this updated version also converges more
reliably.

lrtest now handles models with no RHS variables.

ml **graph** did not work when there were more than 10 iterations; it now does.

xtgls would, for some models, reset the **iis** and **tis** variables so that they were
interchanged. This is fixed.

----- **update 13may1999** --------------------------------------------------------

collapse previously produced a float result when working with long variables
and now produces a double result, thus maintaining all possible precision.

heckprob now works correctly for selection dependent variables that are
zero/not zero. Previously, it required that the selection dependent
variable be 0/1.

reshape mislabeled the heading of its report when reshaping from long to wide.
It said "wide -> long" when it should have said "long -> wide".

stset's **exit(***var***=***numlist***)** option would not work if numlist contained more than
one variable.

----- **update 05may1999** --------------------------------------------------------

prais issued an error message when used with more than 10 or 20 variables. Now
it is fixed.

----- **update 27apr1999** --------------------------------------------------------

arima and arch. To make the interpretation of dynamic predictions more
consistent for a wider range of models, the meaning of the **dynamic()** option
has changed. Now, all references to the dependent variable, say y, prior
to the time period specified in **dynamic()** evaluate to the observed (not
predicted) value of y; all values of y on or after **dynamic()** evaluate to
the predicted value of y.

xi would not work with time-series operators if the dataset was tsset as panel
data.

----- **update 26apr1999** --------------------------------------------------------

tabi now works correctly with larger than 9 x k or k x 9 tables.

----- **update 23apr1999** --------------------------------------------------------

grmeanby did not work when weights were specified.

ivreg would fail if the number of instruments exceeded about 450.

ltable did not present the log-rank test if weights were specified.

pause now runs in version-6 mode, meaning commands you type in debug mode are
interpreted according to the modern rules.

sttocc did not necessarily reselect the same "random" sample when rerun with
the same random-number seed; it now does. In addition, **sttocc**'s **match()**
option now allows a varlist rather than just a varname.

stmh did not, under certain conditions, report results when option **by()** was
specified.

sts now uses the value labels to label graphs when you have attached value
labels to the analytic time variable **_t** (as unlikely as that may be).

----- **update 21apr1999** --------------------------------------------------------

**Stata executable**(*), all platforms.
**cox** and stcox now have a new **noadjust** option for use with the **robust**
option. This option prevents the estimated variance matrix from being
multiplied by N/(N-1) or g/(g-1) (g the number of clusters). Most users
will probably not wish to use this new option.

gettoken and tokenize now support long macros.

*.pkg files may now contain "**f ../**etc." references to mean parent
directory.

**Stata executable**(*), Unix.
Some users saw $<#> in help files when text was supposed to be highlighted.
The text is now shown in highlighted form just as intended.

----- **update 12apr1999** --------------------------------------------------------

On-line help and search index brought up to date for STB-48.

----- **update 02apr1999** --------------------------------------------------------

adjust. The reported standard errors were incorrect when some variables were
left unspecified. Results were correct when every variable in the model
was specified either in the varlist or in the **by()** option.

arima and arch could not estimate models if there were insufficient contiguous
observations for the starting value algorithm. In such cases, they now
default to starting values of 0 for the ARMA and/or ARCH parameters.

hausman has new options **prior()** and **current()** to allow the labels for the
coefficient columns to be changed.

heckman. The counts of censored and uncensored observations were reversed in
the output.

heckprob. (1) The **noconstant** option was not honored in the selection equation;
it now is. (2) When there were missing values among the RHS variables of
the primary equation for observations that were not selected, these
observations were incorrectly omitted from the estimation sample. (3)
Better starting values are now used so models should converge more quickly.

integ incorrectly required the user to specify the **generate()** option.

istdize would sometimes mistakenly issue the error message that the number of
cases exceeded the population size and so refused to run, even when that
was not true.

kdensity's **title()** option now understands **title(" ")** to mean no title is to be
displayed and the **title()** option will accept compound double quotes.

quadchk now works with xtintreg.

scobit's model test is deleted because the ancillary parameter alpha and the
constant are not both identifiable in the constant-only model. **scobit** now
also converges more reliably.

xtgls. (1) **xtgls** now reports the correct log-likelihood. (2) Previously, if
option **igls** was specified, **xtgls** reported consistent, iterated results, but
these were not the MLE; now MLE results are produced. (3) Previously, when
**panel(correlated)** was specified without option **igls**, the GLS matrix was
based on a panel-heteroskedastic model. It is now computed from OLS. Both
yield consistent results but the new approach is more in line with what
most people would expect.

xtnbreg**, fe** now explicitly omits all observations that do not contribute to the
likelihood (for example, groups of size one). **xtnbreg**, both **fe** and **re**,
also now converges more reliably for difficult problems.

xtpois**, fe** now explicitly omits all observations that do not contribute to the
likelihood (for example, groups of size one). **xtpois, re normal** now
converges more reliably for the constant-only model.

----- **update 19mar1999** --------------------------------------------------------

snapspan refused to transform the data and instead issued a syntax error when
there was more than one event variable in the dataset.

tabodds. When weights were used, the score test for trend reported by **tabodds**
was incorrect. (All other statistics were fine.) The problem has been
fixed.

----- **update 15mar1999** --------------------------------------------------------

nbreg has been enhanced to optionally estimate an alternative parameterization
of the negative binomial model. Choosing the option **dispersion(constant)**
yields a model in which the overdispersion is constant from observation to
observation. See help nbreg for details.

stphplot would sometimes connect the points in the resulting graph in an odd
order.

xtnbreg**, fe** should have included a constant term, but it did not. When weights
were specified in the **re** and **fe** models, it would not converge to the right
answer; it now converges reliably. The comparison model for the **re** case is
the new **nbreg, dispersion(constant)** alternative parameterization. The
command is now much faster as well.

xtpois**, re** (without weights) could sometimes have a problem converging. When
weights were specified in the **re** and **fe** models, it would not converge to
the right answer. It now converges reliably with and without weights, and
it is much faster as well.

----- **update 04mar1999** --------------------------------------------------------

fracpoly. The way the **adjust()** option works has changed.

sw now works with ologit and oprobit.

**Stata executable**(*), all platforms.
When version is set to 5, label **save** now produces files compatible with
Stata 5.0.

**cox** and stcox no longer allow specifying option **robust** with **mexact** or
**pexact** options.

ologit and oprobit now report the Wald model chi2 statistic if option
**offset()** is specified.

inspect caused fracpoly to crash under certain circumstances; that is
fixed.

**Stata for Mac executable**(*).
profile.do can now be located in a folder that contains spaces in its name.

The Log button is now synchronized with the command line.

**Stata for Windows executable**(*).
The Review window now maintains its size even when used with TrueType
fonts.

profile.do can now be located in a folder that contains spaces in its name.

With some printers, the do-file editor would only print on a quarter of a
page. It now prints on the whole page.

----- **update 22feb1999** --------------------------------------------------------

cnsreg was not saving the log-likelihood.

dstdize's **saving()** option now works and its **base()** option now works with value
labels.

heckman's **mills()** option did not work if an optional dependent variable was
specified simultaneously with the **select()** option. In addition, option
**nshazard()** has been added as a synonym for **mills()** because it more
accurately describes what is calculated (nshazard stands for nonselection
hazard).

linktest would not run if you set version prior to 6.

lrtest. The reported degrees-of-freedom for the test would be incorrect if the
estimator's option **constraints()** was used in the estimation of either model
and it was the constraint being tested. (This could only affect reg3 and
mlogit).

strate's **jackknife** option now works with pweights and iweights.

svylc**, show** did not work; it now does.

----- **update 10feb1999** --------------------------------------------------------

areg. **predict** after **areg** did not take into account weights if they were
specified.

bs has been improved so as to post a missing value when a statistic cannot be
calculated, or when the bootstrap sample causes the estimation command to
produce an error.

bs, bstrap, bsample gave an error message when the **cluster()** or **size()** options
were specified. These options now work.

bstat now handles missing values on a variable-by-variable basis.

fracpred. Typing **fracpred** *newvar***, for(***xvar***)** where *xvar* was not a predictor
produced an incorrectly worded error message.

streg**, dist(gamma)** could produce the message "initial values invalid", and then
refuse to estimate the model, if **_t** in the first observation was missing.

svymean, svytotal, and svyratio gave an error message when they encountered
value labels longer than 8 characters.

svymlog gave an error message when it encountered value labels with embedded
quotes.

xi could not be used with the version-5 (backward compatibility mode) st
commands or other version-5 commands.

----- **update 28jan1999** --------------------------------------------------------

**Stata executable**(*), all platforms.
The outfile command did not respect date formats.
The sysdir **set** command incorrectly handled trailing slashes.

**Stata for Windows executable**(*).
If an application such as //www.stata.com/quest":StataQuest changed the
**Help** menu, later the original menu bar could not be restored.

----- **update 27jan1999** --------------------------------------------------------

**Stata for Mac executable**(*).
In some cases, Stata had difficulty finding its library that allows it to
communicate over the Internet.

----- **update 19jan1999** --------------------------------------------------------

**Stata executable**(*), all platforms.
Expressions containing nested, compound double quotes (e.g, `"`"this"'"')
in which the quoted string itself contained +, -, *, /, would result in a
syntax error.

**Stata for Windows executable**(*).
File--Close did nothing under the do-file editor, although the Close button
did work. In addition, double clicking on very long lines in the Review
window would cause the line to be truncated when executed.

**Stata for Mac executable**(*).
Long string variables (longer than 20 characters) could cause problems in
the data editor.

----- **update 13jan1999** --------------------------------------------------------

gnbreg. The degrees of freedom for the likelihood ratio test of alpha=0
(comparison with Poisson model) were set to one in all cases. The degrees
of freedom should be the number of parameters in the **lnalpha** equation.
This is fixed.

heckprob did not honor **if** *exp* or **in** *range*.

-------------------------------------------------------------------------------