What’s new in survival data
- Contrasts, which is to say, tests of
linear hypotheses involving factor variables and their interactions
from the most recently fit model. Tests include ANOVA-style tests of
main effects, simple effects, interactions, and nested effects. Effects
can be decomposed into comparisons with reference categories,
comparisons of adjacent levels, comparisons with the grand mean, and
more. New commands contrast and margins, contrast are
available after stcox, stcrreg, and streg.
- Pairwise comparisons of
means, estimated cell means, estimated marginal means, predictive
margins of linear and nonlinear responses, intercepts, and slopes. In
addition to ANOVA-style comparisons, comparisons can be made of
population averages. New commands pwcompare and margins,
pwcompare are available after stcox, stcrreg, and
- Graphs of margins, marginal
effects, contrasts, and pairwise comparisons. Margins and effects can
be obtained from linear or nonlinear (for example, probability)
responses. New command marginsplot is available after
stcox, stcrreg, and streg.
- Estimation output improved.
- Implied zero coefficients now shown. When a coefficient is
omitted, it is now shown as being zero, and the reason it was
omitted—collinearity, base, empty—is shown in the
standard-error column. (The word “omitted” is shown if
the coefficient was omitted because of collinearity.)
- You can set displayed precision for all values in coefficient
tables using set cformat, set pformat, and set
sformat. Or you may use options cformat(),
pformat(), and sformat() now allowed on all
- Estimation commands now respect the width of the Results window.
This feature may be turned off by new display option
- You can now set whether base levels, empty cells, and omitted are
shown using set showbaselevels, set showemptycells,
and set showomitted.
- Gönen and Heller’s K concordance coefficient
available after Cox proportional hazards estimation. K is
robust to censoring.
- Option addplot() now places added graphs above or below. Graph
commands that allow option addplot() can now place the added
plots above or below the command’s plots. Affected by this are
the commands ltable, stci, stcoxkm,
stcurve, stphplot, strate, sts graph, and
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New in Stata 13
for more about what was added in Stata 13.