Variables and outcomes

Define measurements and event ascertainment

Operational definitions translate clinical concepts into recorded variables. Retain code versions, look-back windows and validation evidence. Distinguish a missing measurement from a measured absence and examine differential outcome capture.

Flow diagram

Steps

Define constructs and objectives

Map each objective to an observable measurement.

Specify operational definitions

Document code lists, algorithms, source fields and validation evidence.

Define outcomes

Record outcome scale, assessment timing and event ascertainment.

Define measurement windows

Specify baseline and repeated assessment rules.

Specify missing and ambiguous values

Prespecify rules for partial, conflicting and unavailable measurements.

Review definitions and evidence

Verify construct validity and expected measurement limitations.