Table 4.

Problems Identified from Informant Interviews

Problem	Details
Choice and specification of measurement tools
Length	Shorter tools decrease feasibility but may also limit power to differentiate
Usability	Ability to allow indicators to discriminate quality of care among providers
Measuring constructs of health	Self-report vs objective measures (e.g., gait speed)
Data collection problems
Proxy respondents	Increase representativeness but decrease validity
Clinical usefulness	Usability for providers
Completeness of data	Low response rates, representativeness
Population for sampling	Targeting population with multiple chronic conditions important, but challenging to define