help estimates save dialogs: estimates save
estimates use
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Title
[R] estimates save -- Save and use estimation results
Syntax
estimates save filename [, append replace]
estimates use filename [, number(#)]
estimates esample: [varlist] [if] [in] [weight]
[, replace stringvars(varlist) zeroweight]
estimates esample
Menu
estimates save
Statistics > Postestimation > Manage estimation results > Save to
disk
estimates use
Statistics > Postestimation > Manage estimation results > Load from
disk
Description
estimates save filename saves the current (active) estimation results in
filename.
estimates use filename loads the results saved in filename into the
current (active) estimation results.
In both cases, if filename is specified without an extension, .ster is
assumed.
estimates esample: (note the colon) resets e(sample). After estimates
use filename, e(sample) is set to contain 0, meaning that none of the
observations currently in memory was used in obtaining the estimates.
estimates esample (without a colon) displays how e(sample) is currently
set.
Options
append, used with estimates save, specifies that results be appended to
an existing file. If the file does not already exist, a new file is
created.
replace, used with estimates save, specifies that filename can be
replaced if it already exists.
number(#), used with estimates use, specifies that the #th set of
estimation results from filename be loaded. This assumes that
multiple sets of estimation results have been saved in filename by
estimates save, append. The default is number(1).
replace, used with estimates esample:, specifies that e(sample) can be
replaced even if it is already set.
stringvars(varlist), used with estimates esample:, specifies string
variables. Observations containing variables that contain "" will be
omitted from e(sample).
zeroweight, used with estimates esample:, specifies that observations
with zero weights are to be included in e(sample).
Remarks
See [R] estimates for an overview of the estimates commands.
For a description of estimates save and estimates use, see Saving and
using estimation results in [R] estimates.
The rest of this entry concerns e(sample).
Remarks are presented under the following headings:
Setting e(sample)
Resetting e(sample)
Determining who set e(sample)
Setting e(sample)
After estimates use filename, the situation is nearly identical to what
it was immediately after you fit the model. The one difference is that
e(sample) is set to 0.
e(sample) is Stata's function to mark which observations among those
currently in memory were used in producing the estimates. For instance,
you might type
. regress mpg weight displ if foreign
(output omitted)
. summarize mpg if e(sample)
(output omitted)
and summarize would report the summary statistics for the observations
regress in fact used, which would exclude not only observations for which
foreign=0 but also any observations for which mpg, weight, or displ was
missing.
If you saved the above estimation results and then reloaded them,
however, summarize mpg if e(sample) would produce
. summarize mpg if e(sample)
Variable | Obs Mean Std. Dev. Min Max
-------------+--------------------------------------------------------
mpg | 0
Stata thinks that none of these observations was used in producing the
estimates currently loaded.
What else could Stata think? When you estimates use filename, you do not
have to have the original data in memory. Even if you do have data in
memory that look like the original data, it might not be. Setting
e(sample) to 0 is the safe thing to do. There are some postestimation
statistics, for instance, that are appropriate only when calculated on
the estimation sample. Setting e(sample) to 0 ensures that, should you
ask for one of them, you will get back a null result.
We recommend that you leave e(sample) set to 0. But what if you really
need to calculate that postestimation statistic? Well, you can get it,
but you are going to take responsibility for setting e(sample) correctly.
Here we just happen to know that all the foreign observations were used,
so we can type
. estimates esample: if foreign
If all the observations had been used, we could simply type
. estimates esample:
The safe thing to do, however, is to look at the estimation command --
estimates describe will show it to you -- and then type
. estimates esample: mpg weight displ if foreign
Resetting e(sample)
estimates esample: will allow you to not only set but also reset
e(sample). If e(sample) has already been set (say that you just fit the
model) and you try to set it, you will see
. estimates esample: mpg weight displ if foreign
no; e(sample) already set
r(322);
Here you can specify the replace option:
. estimates esample: mpg weight displ if foreign, replace
We do not recommend resetting e(sample), but the situation can arise
where you need to. Imagine that you estimates use filename, you set
e(sample), and then you realize that you set it wrong. Here you would
want to reset it.
Determining who set e(sample)
estimates esample without a colon will report whether and how e(sample)
was set. You might see
. estimates esample
e(sample) set by estimation command
or
. estimates esample
e(sample) set by user
or
. estimates esample
e(sample) not set (0 assumed)
Saved results
estimates esample without the colon saves macro r(who), which will
contain cmd, user, or zero'd.
Also see
Manual: [R] estimates save
Help: [R] estimates
