Table 2.

Methodological framework for establishing feasibility, validity and reliability

Stage	Process
Proof of concept–feasibility	1. Field testing and pilot testing of measure in controlled and free-living settings
Content and Face validity	2. Examination of relevant literature 3. Consultation with relevant experts 4. Theoretical examination of measure and domain/dimension 5. Examination of proposed data processing and decision algorithms including sensitivity analysis
Convergent validity	6. Assessment of the agreement between your measure and an existing (non-criterion) measure
Criterion validity	7. Assessment of the agreement between your measure and a criterion measure
Internal validity	8. Examination of bias such as reactivity and missing data
External validity	9. Examination of sample bias (age, sex, ethnic origin, socio-economic status)
Inter-rater reliability	10. Assessment of stability of tests administered by different researchers
Inter-instrument reliability	11. Assessment of stability of tests administered using multiple versions of the same instrument
Test-retest reliability	12. Assessment of stability of consecutive tests
Behavioural reliability	13. Assessment of stability accounting for behavioural changes
Context validity	14. Based on all assessments, will measure give useful information in the proposed context?
Purpose validity	15. Based on all assessments and considering study design, are the validity and reliability results suitable for the proposed use and likely to allow the research question to be answered?