What’s new in survey data

• Survey estimation may be combined with new SEM for structural equation modeling.
• Survey feature support for multilevel models, xtmixed, including multilevel sampling weights and robust variance estimators.
• Bootstrap standard errors for survey data using user-supplied bootstrap replicate weights.
• Survey SDR weights, which is to say, successive difference replicate weights, which are supplied with many datasets from the U.S. Census Bureau.
• 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 svy.
• 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 svy.
• 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 svy.
• 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.
  • Estimation commands now respect the width of the Results window. This feature may be turned off by new display option nolstretch.
  • You can now set whether base levels, empty cells, and omitted are shown using set showbaselevels, set showemptycells, and set showomitted.
• Survey goodness-of-fit available after logistic, logit, and probit with new command estat gof.
• Survey coefficient of variation (CV) available with new command estat cv.

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See New in Stata 12 for more about what was added in Stata Release 12.