Context: The validated 82-item Advance Care Planning (ACP) Engagement Survey measures a broad range of ACP behaviors but is long.
Objectives: Determine whether shorter survey versions (55-item, 34-item, 15-item, 9-item, and 4-item versions) can detect similar change in response to two well-validated ACP interventions and provide practical effect size information.
Methods: We assessed ACP engagement for 986 English- and Spanish-speaking adults in a randomized trial of PREPARE vs. an advance directive-only study arms. The survey was administered at baseline, one week, three months, six months, and 12 months. We calculated mean change scores from baseline to follow-up time points by study arm, intraclass correlation coefficients of change scores between the 82-item survey with shorter versions, and within-group and between-group effect sizes of the mean change scores.
Results: Shorter survey versions were able to detect within-group and between-group changes at all time points. Within-group intraclass correlations of the 82-item to shorter versions were high (0.78-0.97), and the amount of between-group differences was comparable using all survey versions. Twelve-month within-group effect sizes ranged narrowly from 0.76 to 1.05 for different survey versions in the PREPARE arm and from 0.44 to 0.64 for the advance directive-only version. Between-group effect sizes ranged narrowly from 0.24 to 0.30 for different survey versions. Results were similar when stratified by English and Spanish speakers.
Conclusion: Shorter versions of the ACP Engagement Survey were able to detect within-group and between-group changes comparable with the 82-item version and can be useful for efficiently and effectively measuring ACP engagement in research and clinical settings.
Keywords: Advance care planning; psychometrics; surveys and questionnaires.
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