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Thinking in Data Domains

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A practical way to understand large data sets is to organize variables into logical domains.

A domain is a group of variables that belong together because they describe the same type of information or originate from the same part of the data collection process.

Common domain patterns

Survey waves

  • baseline assessments
  • follow-up surveys
  • annual visits
  • sub-study questionnaires

Clinical domains

  • imaging or radiology
  • genetics
  • laboratory measurements
  • pulmonary or cardiac assessments
  • medication and treatment history

Participant characteristics

  • age
  • sex
  • mutation type
  • enrollment site
  • disease severity

Variable types

  • date variables
  • continuous measurements
  • categorical variables
  • text fields

Why this helps

Thinking in domains helps analysts:

  • reconstruct study design
  • plan exploratory analysis
  • organize cleaning work
  • communicate more clearly with collaborators
  • turn a huge variable list into a meaningful system