help statsby dialog: statsby
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Title
[D] statsby -- Collect statistics for a command across a by list
Syntax
statsby [exp_list] [, options ]: command
options description
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Main
* by(varlist [, missing]) equivalent to interactive use of by varlist:
Options
clear replace data in memory with results
saving(filename, ...) save results to filename; save statistics in
double precision; save results to filename
every # replications
total include results for the entire dataset
subsets include all combinations of subsets of groups
Reporting
nodots suppress the replication dots
noisily display any output from command
trace trace the command
nolegend suppress table legend
verbose display the full table legend
Advanced
basepop(exp) restrict initializing sample to exp; seldom
used
force do not check for svy commands; seldom used
forcedrop retain only observations in by-groups when
calling command; seldom used
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* by() is required on the dialog box because statsby is useful to the
interactive user only when using by().
All weight types supported by command are allowed except pweights; see
weight.
Menu
Statistics > Other > Collect statistics for a command across a by list
Description
statsby collects statistics from command across a by list. Typing
. statsby exp_list , by(varname): command
executes command for each group identified by varname, building a dataset
of the associated values from the expressions in exp_list. The resulting
dataset replaces the current dataset, unless the saving() option is
supplied.
command defines the statistical command to be executed. Most Stata
commands and user-written programs can be used with statsby, as long as
they follow standard Stata syntax and allow the if qualifier. The by
prefix cannot be part of command.
exp_list specifies the statistics to be collected from the execution of
command. The expressions in exp_list follow the grammar given in
exp_list. If no expressions are given, exp_list assumes a default
depending upon whether command changes results in e() and r(). If
command changes results in e(), the default is _b. If command changes
results in r() (but not e()), the default is all the scalars posted to
r(). It is an error not to specify an expression in exp_list otherwise.
Options
+------+
----+ Main +-------------------------------------------------------------
by(varlist [, missing]) specifies a list of existing variables that would
normally appear in the by varlist: section of the command if you were
to issue the command interactively. By default, statsby ignores
groups in which one or more of the by() variables is missing.
Alternatively, missing causes missing values to be treated like any
other values in the by-groups, and results from the entire dataset
are included with use of the subsets option. If by() is not
specified, command will be run on the entire dataset. varlist can
contain both numeric and string variables.
+---------+
----+ Options +----------------------------------------------------------
clear specifies that it is okay to replace the data in memory, even
though the current data have not been saved to disk.
saving(filename [, suboptions]) creates a Stata data file (.dta file)
consisting of (for each statistic in exp_list) a variable containing
the replicates.
See help prefix_saving_option, for details about suboptions.
total specifies that command be run on the entire dataset, in addition to
the groups specified in the by() option.
subsets specifies that command be run for each group defined by any
combination of the variables in the by() option.
+-----------+
----+ Reporting +--------------------------------------------------------
nodots suppresses display of the replication dots. By default, one dot
character is printed for each by-group. A red `x' is printed if
command returns with an error or one of the values in exp_list is
missing.
noisily causes the output of command to be displayed for each by-group.
This option implies the nodots option.
trace causes a trace of the execution of command to be displayed. This
option implies the noisily option.
nolegend suppresses the display of the table legend, which identifies the
rows of the table with the expressions they represent.
verbose requests that the full table legend be displayed. By default,
coefficients and standard errors are not displayed.
+----------+
----+ Advanced +---------------------------------------------------------
basepop(exp) specifies a base population that statsby uses to evaluate
the command and to set up for collecting statistics. The default
base population is the entire dataset, or the dataset specified by
any if or in conditions specified on the command.
One situation where basepop() is useful is collecting statistics over
the panels of a panel dataset by using an estimator that works for
time series, but not panel data, e.g.,
. statsby, by(mypanels) basepop(mypanels==2): arima ...
force suppresses the restriction that command not be a svy command.
statsby does not perform subpopulation estimation for survey data, so
it should not be used with svy. statsby reports an error when it
encounters svy in command if the force option is not specified. This
option is seldom used, so use it only if you know what you are doing.
forcedrop forces statsby to drop all observations except those in each
by-group before calling command for the group. This allows statsby
to work with user-written commands that completely ignore if and in
but do not return an error when either is specified. forcedrop is
seldom used.
Example: Collecting coefficients
. sysuse auto
. statsby, by(foreign): regress mpg gear turn
Example: Collecting both coefficients and standard errors using a time-series e
> stimator with panel data
. webuse grunfeld, clear
. tsset company year
. statsby _b _se, basepop(company==1) by(company): arima invest mvalue
kstock, ar(1)
Example: Collecting results saved in r-class macros
. sysuse auto, clear
. statsby mean=r(mean) sd=r(sd) size=r(N), by(rep78): summarize mpg
Also see
Manual: [D] statsby
Help: [P] postfile, [D] collapse, [R] bootstrap, [R] jackknife, [R]
permute, [D] by
