Stata 15 help for adjust

help adjust dialog: adjust ------------------------------------------------------------------------------- adjust has been superseded by margins. Except for adjust's generate() and stdf options, the margins command can do everything that adjust did and more. margins syntax differs from adjust; see margins. adjust continues to work but does not support factor variables and will often fail if you do not run your estimation command under version control, with the version set to less than 11. This help file remains to assist those who encounter an adjust command in old do-files and programs.

Title

[R] adjust -- Tables of adjusted means and proportions

Syntax

adjust [var[= #] ...] [if] [in] [, options]

options Description ------------------------------------------------------------------------- Main by(varlist) compute and display predictions for each level of variables

Options xb linear prediction; the default pr predicted probabilities exp exponentiated linear prediction se display standard error of the prediction; default is none stdf display standard error of the forecast; default is none ci display confidence or prediction intervals level(#) set confidence level; default is level(95) vertical stack confidence intervals equation(eqno) use eqno equation in a multiple-equation system nooffset ignore offset or exposure variable (if any) when making predictions generate(newvar1 [newvar2]) generate prediction variable, error variable

More options replace replace data in memory with table label(text) prediction label selabel(text) error-term label cilabel(text) confidence interval label format(%fmt) display format for numbers in table nokey suppress table key noheader suppress table header center center numbers in cells; default is to right-align left left-align column labels; default is to right-align cellwidth(#) cell width csepwidth(#) column separation scsepwidth(#) supercolumn separation stubwidth(#) left stub width -------------------------------------------------------------------------

Menu

Statistics > Postestimation > Adjusted means and proportions

Description

After an estimation command (see [I] estimation commands), adjust provides adjusted predictions of xb (the means in a linear-regression setting), probabilities (available after some estimation commands), or exponentiated linear predictions. The estimate is computed for each level of the by() variables, setting the variables specified in [var[= #] ...] to their mean or to the specified number if the = # part is specified. If by() is not specified, adjust produces results as if by() defined one group. Variables used in the estimation command but not included in either the by() variable list or the adjust variable list are left at their current values, observation by observation. Here adjust displays the average estimated prediction (or the corresponding probability or exponentiated prediction), substituting the mean of these unspecified variables within each group defined by the variables in the by() option.

Options

+------+ ----+ Main +-------------------------------------------------------------

by(varlist) specifies the variables whose levels determine the subsets of the data for which adjusted predictions are to be computed. The variables in by() need not have been involved in the original estimation command. A maximum of seven variables may be specified in the by() option. If by() is not specified, the results are computed treating all the data as one group.

+---------+ ----+ Options +----------------------------------------------------------

xb, the default, specifies that the linear prediction from the estimation command be displayed. This produces a predicted value (a mean in the linear-regression setting) and is equivalent to the xb option of predict. Depending on the estimation command, the xb value may not be in the original units of the dependent variable.

pr is an alternative to xb that specifies that the predicted probability be displayed. The pr option is not available after all commands.

exp is an alternative to xb that specifies that exponentiated linear prediction, exp(xb), be displayed. Depending on the estimation command, the resulting quantity might be called an "incidence rates", a "hazard ratios", etc.

se specifies that the standard error of the linear prediction be displayed. This is equivalent to the stdp option of predict.

stdf specifies that the standard error of the forecast of the linear prediction be displayed. This is equivalent to the stdf option of predict and is available only after estimation commands that support the stdf predict option.

ci specifies that a confidence interval be displayed. The confidence interval is for the displayed estimate as determined by the xb, pr, or exp option -- producing an interval for the adjusted linear prediction, probability, or exponentiated linear prediction. When stdf is specified, a prediction interval is produced, which is, by definition, wider than the corresponding confidence intervals.

level(#) specifies the confidence level, as a percentage, for confidence or prediction intervals. The default is level(95) or as set by set level.

vertical requests that the endpoints of confidence or prediction intervals be stacked vertically on display. You must specify more than two variables in the by() option for vertical results to be produced.

equation(eqno) specifies the equation in a multiple-equation system that is to be used in the adjust command. This option is allowed only after multiple-equation estimation commands.

nooffset is relevant only if you specified offset(varname) or exposure(varname) when you fit your model. It modifies the calculations made by adjust so that they ignore the offset or exposure variable.

generate(newvar1 [newvar2]) generates one or two new variables. If one variable is specified, the adjusted linear prediction for each observation is generated in newvar1 (holding the appropriate variables to their means or to other specified values). If pr is specified, the adjusted linear prediction is transformed to a probability. If exp is specified, the exponentiated prediction is returned. If newvar2 is specified, the standard error from either the se option or the stdf option is placed in the second variable.

+--------------+ ----+ More options +-----------------------------------------------------

replace specifies that the data in memory be replaced with data containing 1 observation per cell corresponding to the table produced by the adjust command.

label(text), selabel(text), and cilabel(text) allow you to change the labels for the displayed predictions (from the xb, pr, or exp option), error terms (from the se or stdf option), and confidence intervals (from the ci option). label() and selabel() also change the variable labels for the variables created by the generate() option.

format(%fmt) specifies the display format for presenting the numbers in the table; see [U] 12.5 Formats: Controlling how data are displayed. format(%8.0g) is the default. Standard errors and confidence intervals are further formatted for output by automatic enclosure within parentheses or square brackets.

nokey and noheader suppress the display of the table key and header information.

center specifies that results be centered in the table's cells. The default is to right-align the results. For centering to work well, specify a display format, too, such as format(%9.2f).

left specifies that column labels be left-aligned. The default is to right-align them to distinguish them from supercolumn labels, which are left-aligned.

cellwidth(#) specifies the width of the cell in units of digit widths; 10 means the space occupied by 10 digits, which is 0123456789. The default is not a fixed number but a number chosen to spread the table out while presenting a reasonable number of columns across the page.

csepwidth(#) specifies the separation between columns in units of digit widths. The default is not a fixed number but a number chosen according to what Stata thinks looks best.

scsepwidth(#) specifies the separation between supercolumns in units of digit widths. The default is not a fixed number but a number chosen according to what Stata thinks looks best.

stubwidth(#) specifies the width of the left stub of the table in units of digit widths. The default is not a fixed number but a number chosen according to what Stata thinks looks best.

Remarks

adjust is a postestimation command; see postest. adjust is really just a front-end process for predict. It sets up the values at which predictions are desired and then displays the predictions in tabular form; the data remain unchanged. adjust's options control the labeling of the predictions, errors, and confidence intervals. tabdisp is used to produce the final table.

If you have restricted your estimation command to a portion of the data by using if or in, then you will generally want to use the same conditions with adjust. This task is easily done by including if e(sample) with the adjust command. However, there may be legitimate reasons for using different data to perform the estimation and to obtain adjusted predictions (that is, out-of-sample adjusted predictions).

Examples

regress

Setup . sysuse auto . regress price mpg weight turn foreign . adjust mpg weight turn, by(foreign) . adjust mpg weight turn, by(foreign) se ci . adjust mpg weight turn, by(foreign) stdf ci

Setting some variables to specific values instead of their mean . adjust mpg=25 weight turn=35.2, by(foreign)

Generating variables containing the predictions and errors . adjust mpg weight, by(foreign) gen(pred err) se

Using multiple by() variables, which need not have been used in the estimation command . adjust mpg weight, by(foreign rep78) se ci

Setting a variable and using it as a by() variable . sysuse auto, clear . regress price mpg weight turn foreign . adjust weight foreign=0, by(foreign) se

Compare this with . adjust weight, by(foreign) se

and this . adjust weight foreign=1, by(foreign) se

logit

Setup . sysuse auto . logit foreign weight mpg

Obtain predicted probabilities for each level of rep78, setting mpg to its mean . adjust mpg, by(rep78) pr

anova

Setup . webuse sysage, clear . anova systolic drug disease drug*disease age, continuous(age)

Obtain adjusted means and standard errors by disease and drug . adjust age, by(disease drug) se

mvreg

Setup . sysuse auto . mvreg weight length turn = displ foreign

Obtain statistics from various equations after fitting a multivariate model . adjust displ, by(foreign) equation(length) se ci . adjust displ, by(foreign) equation(#3) se ci

Also see

Manual: [R] adjust

Help: [R] table


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