Considering the balance: development of a scale to assess patient views on trade-offs in competing health outcomes.

OBJECTIVES

To describe the development of a scale assessing participant attitudes regarding two commonly encountered trade-offs: quality versus quantity of life and present versus future health.

DESIGN

Observational cohort study.

SETTING

Community.

PARTICIPANTS

Three hundred and fifty-seven community-dwelling adults aged 65 and older.

MEASUREMENTS

An initial set of 20 items rated on a 5-point Likert scale of agreement was reduced using principal components analysis. Construct validity was evaluated through comparison of the scale with other tools addressing the same trade-offs and analysis of participant characteristics associated with attitudes favoring quality over quantity of life and present over future health. Internal consistency was assessed using Cronbach alpha. Test-retest reliability was assessed using intraclass correlation coefficients (ICCs).

RESULTS

The scale consists of two subscales, each addressing one trade-off, with a total of 10 items. All factor loadings were 0.5 and greater, and subscale scores were significantly different (P ≤ .05) in the expected directions when comparing with other tools and with participant race, education, and religious identity. Internal consistency was good (Cronbach α 0.85 and 0.84), and test-retest reliability was fair (ICCs 0.63 and 0.47). Subscale score medians fell near the middle of each scale, with narrow interquartile ranges, but more than 15% of the sample scored at an extreme of each subscale.

CONCLUSION

This new scale captures views on two common trade-offs in health care. Although test-retest reliability was modest, its high validity suggests that this tool can be used to familiarize people with common trade-offs and further explore influences on attitudes.