Background The objective of this study was to test the data quality, test–retest reliability and hospital-level reliability of the Patient-Reported Incident in Hospital Instrument (PRIH-I).

Methods 13 incident questions were included in a national patient-experience survey in Norway during the spring of 2011. All questions and a composite incident index were assessed by calculating missing-item rates, test–retest reliability and hospital-level reliability. A multivariate linear regression on a global item regarding incorrect treatment was used to assess the main sources of variation in patient-perceived incorrect treatment at hospitals.

Results Five of the 13 patient-incident questions had a missing-item rate of >20%. Only one item met the criterion of 0.7 for test–retest reliability (wrong or delayed diagnosis), seven items had a score of >0.5, while the remainder had a reliability score of <0.5. However, the reliability was >0.7 for six of 10 items tested at the hospital level, and >0.6 for the remaining four items. A patient-incident index based on 12 of the incident items had no missing data, the test–retest reliability was 0.6 and the hospital-level reliability was 0.85.

Conclusions The PRIH-I comprises 13 questions about patient-perceived incidents in hospitals, and can be easily and cost-effectively included in national patient-experience surveys with an acceptable increase in respondent burden. Although the missing-item rate and test–retest reliability were poor for several items, the hospital-level reliability was satisfactory for most of the items. The incident items contribute to a patient-reported incident index, with excellent data quality and hospital-level reliability.