Study day variables

Time is a critical measure for clinical trial analysis. Time is captured in clinical trial databases in a study day variable. Study day can be defined as the number of days from therapeutic intervention to any given time point or event. By defining study day, you create a common metric for measuring time across a population of patients in a clinical trial. There can be a study day calculation for any time point of interest. Adverse event start, study termination, and clinical endpoint event date all make good choices for study day calculations. The study day calculation is performed with one of the two following approaches. 

Program 4.3 for creating study day variables for the SDTM data sets. However, the General Considerations document from the CDISC Analysis Data Set Modeling Team states that you should use the algorithm in Program 4.2 for analysis data sets. Whether you are deriving data based on the CDISC models or not, you should calculate study day variables in a consistent fashion across a clinical trial or set of trials for an application. 

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See also in sourсe #XX -- [ , ]

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