Five-point scales outperform 10-point scales in a randomized comparison of item scaling for the Patient Experiences Questionnaire

Objective: To assess the data quality of two approaches to scaling items within the Patient Experiences Questionnaire (PEQ); a five-point scale with descriptors for all scale points and a 10-point scale with descriptors only at the end points.

Study design and setting: The two versions were pretested through cognitive interviews with 14 patients. The PEQ was then mailed to 1,000 patients after inpatient treatment at a large university hospital in Norway, randomized to receive the 5- or 10-point scale versions. Response rates, missing data, item means, floor, and ceiling effects were assessed. Regression analysis was used to examine the impact of response scale on missing data, floor, and ceiling effects after controlling for age, education level, and health status.

Results: The five-point scale produced data with unimodal and fairly symmetric distributions in contrast to the highly skewed J- and U-shaped distributions for the 10-point scale. The five-point scale data had significantly lower item means, floor, and ceiling effects. Regression analysis showed that the type of scale explained a significant component of the variation in both floor and ceiling effects.

Conclusion: The five-point scale performed better than the 10-point scale and is more suitable for assessing patient experiences. The revised PEQ will be used in Norwegian national surveys.