5.6 How should you decide which outcome measures to use?

1) Identify the “things” or “health- related concepts” you want to measure with the client

For example, pain, symptom severity, disability, health- related quality of life

2) Determine the purpose or reason for measuring this health-related concept

Is the intent to describe, predict, or evaluate change over time?

Different outcome measures are developed for different purposes and it is important to choose the measure that is geared towards a specific purpose (see Table 5.2).

3) Search for available outcome measures that can measure a construct with a purpose in mind

Many outcome measures exist to choose from. It is important to review the literature and talk to other health professionals about different outcome measure options available to measure the desired concept.

Consider feasibility such as the length of the outcome measure (e.g. number of items in a questionnaire), the amount of time it takes someone to complete the measure, and literacy requirements if the measure is a self-reported questionnaire.

4) Choose the measure

When choosing a measure, consider:

1. Whether a generic measure or an HIV-specific measure is appropriate
2. Whether an objective or subjective (self-report) measure is appropriate
3. The measurement properties (psychometric adequacy) of the questionnaire, scale or tool. For instance, has the measure been evaluated for reliability and validity with people living with HIV? If evaluating change over time, determine whether this measure is able to detect change over time if change has occurred? And finally, how are the scores on the measure interpreted? What do they mean?