How do I perform multiple comparisons or tests on subtables if I get a significant Pearson chi-square?
There are no multiple comparison methods directly available in PROC FREQ, but there are a number of approaches to consider: • Correspondence analysis is often used as a way to visualize the nonindependence in a table. However, no statistical tests of comparisons are performed. See the examples in the CORRESP chapter of the SAS/STAT User’s Guide. • You could do Pearson chi-square tests on subtables. Use the WHERE statement to select subsets of rows, columns, or both. You can define formats to merge rows or columns if needed. Note, however, that tests on arbitrary subtables will not be independent, and therefore will not partition the chi-square from the original table. It is possible to partition the likelihood ratio chi-square statistic by using certain rules of partitioning the table into a set of 2×2 tables. These rules are outlined in Agresti (2002). Also, because multiple subtables result in multiple tests, adjusting for the multiplicity is important. Consider using the MULTTEST pr
