RE: NONMEM dataset development

From: "Nick Holford" n.holford@auckland.ac.nz Subject: RE: [NMusers] NONMEM dataset development Date: Tue, September 7, 2004 11:57 pm Renee, It does not matter what value (dot, 0, -99, 42) is used to signal a missing covariate. If you need to use that covariate in your model then you must supply code to impute the missing value in order for NONMEM to estimate the covariate effect sensibly. e.g. if AGE is missing then: IF (AGE.LE.0) THEN AGE=60 ; 60 might be the median age in your dataset More complex methods can be used to impute missing values e.g. you could use other known covariates to make a better guess of the missing covariate value. Try searching on Google for 'nonmem missing covariate imputation' and check out some of the links e.g. http://www.cognigencorp.com/nonmem/nm/99sep112000.html Nick _______________________________________________________