These commands specify the key variables for the various regression programs. Key variables depend on the type of data being analyzed and the program being used. The commands described in this section are: CASES, TRIALS and WEIGHT for GMBO; CASES or CC and STRATA or SETNO for PECAN; CASES, CASECOHORT, ENTRY, EVENT, STRATA, TIME, and WEIGHT for PEANUTS; and CASES, PYR, and WEIGHT for AMFIT. Commands that are unique to DATAB are described in Chapters 9 through 12.