The %ITEM macro computes descriptive statistics for analysis of data from a multiple-choice test. Each observation contains the answers from one subject to a set of questions ("items"). The data are compared to an answer key to determine which answers are correct. The score for each subject is computed as the number of correct answers. The output is very similar to that from the ITEM procedure in the SUGI Supplemental library, but several incorrect statistics have been fixed.
NOTE: Beginning in SAS 9.4, this macro is no longer needed. Use the OUTPLC= option in Base SAS PROC CORR to save a matrix of polychoric (or tetrachoric) correlations.
PURPOSE:
The %POLYCHOR macro creates a SAS data set containing a correlation matrix of polychoric correlations or a distance matrix based on polychoric correlations.
This sample combines macro programming with PROC FREQ and DATA Step logic to count the number of missing and non-missing values for every variable in a data set. The results are stored in a data set.
This sample illustrates one method of counting the number of missing and non-missing values for each variable in a data set. Two methods for structuring the resulting data set are shown.
The SELECT macro performs model selection methods for categorical-response models that can be fit in PROC LOGISTIC. These include models using the logit, probit, cloglog, cumulative logit, or generalized logit links. The macro supports binary as well as ordinal and nominal multinomial models.
Standard model selection is done by choosing candidate effects for entry to or removal from the model according to their significance levels. After completion, the set of models selected at each step of this process is sorted on the selected criterion - AUC, R-square, max-rescaled R-square, AIC, or BIC. The requested number of best models on the selected criterion is displayed.
NOTE: Beginning in SAS 9.2, the QIC statistic is produced by PROC GENMOD. Beginning in SAS 9.4 TS1M2, QIC is available in PROC GEE.
PURPOSE:
The %QIC macro computes the QIC and QICu statistics proposed by Pan (2001) for GEE (generalized estimating equations) models. These statistics allow comparisons of GEE models (model selection) and selection of a correlation structure.