Measuring social norms related to handwashing: development and psychometric testing of measurement scales in a low-income urban setting in Abidjan, Côte d'Ivoire.

OBJECTIVES: To design and test the psychometric properties of four context-specific norm-related scales around handwashing with soap after toilet use: (1) perceived handwashing descriptive norms (HWDN); (2) perceived handwashing injunctive norms (HWIN); (3) perceived handwashing behaviour publicness (HWP); and (4) perceived handwashing outcome expectations (HWOE). DESIGN: Scale items were developed based on previous work and pilot tested in an iterative process. Content experts and members of the study team assessed the face validity of the items. The psychometric properties of the scales were assessed in a cross-sectional study. SETTING: The study was conducted in communal housing compounds in Abidjan, Côte d'Ivoire. PARTICIPANTS: A convenience sample of 201 adult residents (≥16 years old) from 60 housing compounds completed the final questionnaire. OUTCOME MEASURE: Confirmatory factor analysis was used to assess the goodness of fit of the global model. We assessed the internal consistency of each scale using Cronbach's alpha (α) and the Spearman-Brown coefficient (ρ). RESULTS: The results of the psychometric tests supported the construct validity of three of the four scales, with no factor identified for the HWOE (α=0.15). The HWDN and HWP scales were internally consistent with correlations of ρ=0.74 and ρ=0.63, respectively. The HWIN scale appeared reliable (α=0.83). CONCLUSION: We were able to design three reliable context-specific handwashing norm-related scales, specific to economically disadvantaged community settings in Abidjan, Côte d'Ivoire, but failed to construct a reliable scale to measure outcome expectations around handwashing. The social desirability of handwashing and the narrow content area of social norms constructs relating to handwashing present significant challenges when designing items to measure such constructs. Future studies attempting to measure handwashing norm-related constructs will need to take this into account when developing such scales, and take care to adapt their scales to their study context.