Transformations to recode existing variables and create additional variables needed for specific analyses are available in all EPICURE programs. The transformation language includes a full set of arithmetic, logical, and relational operators, IF - THEN - ELIF - ELSE - ENDIF statements, and various functions. Transformations may also make use of constants. The basics of the EPICURE command syntax are described in the discussion of the TRAN command in Chapter 3, "Transformation and Subset Selection Commands". This appendix summarizes the general syntax rules for transformations and contains a complete list of the EPICURE operators and functions. Data for all EPICURE programs are stored as single precision (generally four byte) floating point values. Likelihood evaluation and other computations related to modeling in the EPICURE programs are carried out using double precision (generally 8 byte) floating point values. Transformations are carried out for all records in the data set regardless of any subset selection in effect.