I have a design with 2 placebo (plc) doses (a baseline plc, designated 1, to familiarize/stabilize subjects on a lab task) plus three CNS-active doses and an additional plc dose (designated 2-5 and counterbalanced). Performance on the 2 placebo doses is highly correlated and I thus wish the combine the 2 placebos into 1 plc factor in the analytic model (e.g., dose with 4 levels). In the .dat file, the data are in long format with several other DVs and IVs for each subject. Please advise re: how to use egen (or some other technique) to pull this off? To date, I have tried:
1. egen rowmeans for each of the 2 plc doses, then attempted, by subject, to average the 2 newly created variables (result = a variable of blank values).
2. reshape to wide format, then use egen rowmeans (result = error message stating that most of the other IVs and DVs cannot be reshaped to wide format). Thus, I cannot get started without deleting many other variables.
Any suggestions would be most welcome.
Regards,
SD Lane
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