Universal Subject Variable Considerations

Overview

Universal subject variables are attributes about a subject that are applicable across all projects in the StudyTRAX account.  These attributes are typically static (e.g. birth date, race) or seldom change (e.g. contact information).  Universal subject variables are collected only once and can be used in all projects.

Things to Consider

• Birth date, race, ethnicity, gender, death date are common Universal Subject Variables
• Variables that are project specific (e.g. diagnosis, lost to follow-up) should be added into the project as Project Variables instead of Universal Subject Variables
• Variables that can change (e.g. education, marital status, insurance type) should be entered as Project Variables
  • For example, if a subject is enrolled in a study while in college, the education level completed would be marked as high school graduate.  If the subject subsequently enrolls in another study after completing college, the education level would be changed to college graduate.  If education level was a universal variable, then the change made in the second study would change the subject's education level in the first study.  Any analysis completed using education level would be affected with this change, however, at the time of the first study the subject was a high school graduate.
• Contact Information should be entered as a Universal Subject Variable even though it may change as long as it is not used for analysis but to contact the subject.  If a subject moves, then you would want the updated address in all the projects the subject is enrolled in 
• Within a project, universal subject variables can be removed.  Thus, if a project is not collecting subject's birth dates then within the project birth date can be removed without affecting the remaining projects.