To detail the development of the Canadian National Questionnaire on Overdose Monitoring (CNQOM), a questionnaire aimed at assessing the perspectives of key stakeholders towards elements of overdose prevention interventions—supervised consumption sites (SCSs) and overdose hotlines and applications (ORHAs).

Cross-sectional survey.

Canadian health system.

English or French speaking adults from four key informant groups: people who use substances (PWUS), health professionals, emergency responders and the general public.

Test–retest reliability of CNQOM items.

A novel questionnaire was developed. Item development followed a standard approach, with face validity verified by representatives from the four informant groups. Input from experts in harm reduction and addiction medicine enhanced content and face validity of the questionnaire. A rigorous response validation approach was undertaken to ensure respondents were human and from Canada. Test–retest reliability items were assessed using Spearman’s rank correlation, Wilcoxon rank-sum test and Cohen’s kappa.

After data cleaning and response validation, 4445 valid responses were obtained from the four key informant groups. Respondents represented a range of sociodemographic backgrounds and housing scenarios from all provinces and territories in Canada. Test–retest reliability was assessed using a small subsample of 142 participants (primarily from general public informants). Questionnaire items demonstrated slight to substantial stability in responses (kappa coefficients: 0.15–0.58; Spearman’s r: 0.08–0.66).

The CNQOM is the first online questionnaire in Canada designed to capture perspectives and attitudes towards specific elements of SCSs and ORHAs among diverse key informant groups. Our questionnaire was administered to a large, geographically diverse sample and designed to capture the perspectives of four key informant groups. Lower than expected test–retest reliability may be explained by lack of participant familiarity with SCS and especially ORHAs and the impersonal nature of the instrument content among some respondents. Future work will elucidate key informant perspectives on these services based on the data.