Oyvind Bjertnaes, Hilde Hestad Iversen, Andrew M Garratt

Surveys of patients' experiences typically show results that are indicative of positive experiences. Unbalanced response scales have reduced positive skew for responses to items within the Universal Patient Centeredness Questionnaire (UPC-Q). The objective of this study was to compare the unbalanced response scale with another unbalanced approach to scaling to assess whether the positive skew might be further reduced. The UPC-Q was included in a patient experience survey conducted at the ward level at six hospitals in Norway in 2015. The postal survey included two reminders to nonrespondents. For patients in the first month of inclusion, UPC-Q items had standard scaling: poor, fairly good, good, very good, and excellent. For patients in the second month, the scaling was more positive: poor, good, very good, exceptionally good, and excellent. The effect of scaling on UPC-Q scores was tested with independent samples t-tests and multilevel linear regression analysis, the latter controlling for the hierarchical structure of data and known predictors of patient-reported experiences. The response rate was 54.6% (n=4,970). Significantly lower scores were found for all items of the more positively worded scale: UPC-Q total score difference was 7.9 (P<0.001), on a scale from 0 to 100 where 100 is the best possible score. Differences between the four items of the UPC-Q ranged from 7.1 (P<0.001) to 10.4 (P<0.001). Multivariate multilevel regression analysis confirmed the difference between the response groups, after controlling for other background variables; UPC-Q total score difference estimate was 8.3 (P<0.001). The more positively worded scaling significantly lowered the mean scores, potentially increasing the sensitivity of the UPC-Q to identify differences over time and between providers. However, none of the groups exhibited large positive skew and ceiling effects, implying that such effects might not be a big measurement problem for either scaling format. We recommend using the standard scaling in surveys producing external indicators for inter-provider comparisons. The more positively worded scaling has greater relevance for local measurement work where the results of patient experience surveys have shown large positive skew, and intra-provider comparison is the primary goal.