Guessability of standard pharmaceutical pictograms in members of the Nigerian public

BACKGROUND: Pharmaceutical pictograms are standardized images used to visually convey medication instructions. Very little is known about the ability of Africans to interpret these images. OBJECTIVES: Thus, the aim of this study was to assess the guessability (ability to correctly guess meaning) of selected International Pharmaceutical Federation (FIP) and United States Pharmacopoeia (USP) pictograms in members of the Nigerian public. METHODS: A cross-sectional survey was carried out between May and August 2021 on 400 randomly sampled members of Nigerian public. Selected pictograms (24 FIP and 22 USP pictograms) were grouped and printed on A3 sheets of paper which were used to interview members of the public who fulfilled the study's' eligibility criteria. Respondents were asked to guess the meanings of either the FIP or USP pictograms, and their answers written down verbatim. Descriptive and inferential statistics were used to report the data collected. RESULTS: Four hundred respondents were interviewed, with 200 respondents each assessing the guessability of the FIP and USP pictograms. The guessability of assessed FIP pictograms ranged between 3.5 and 95%, while that for the USP pictograms was 27.5–97%. Eleven FIP and Thirteen USP pictograms respectively achieved the International Organization for Standardization (ISO) comprehensibility cutoff point of 67%. Guessing performance (the total number of pictograms correctly guessed by an individual) of respondents that assessed the FIP pictograms was significantly associated with their age (p = 0.044) and highest level of education completed (p = 0.003). For the USP pictograms, guessing performance was only significantly associated with the highest educational level completed (p < 0.001). CONCLUSIONS: Guessability of both pictogram types varied widely, but the guessability of the USP pictograms was generally better than that for the FIP pictograms. Many of the tested pictograms may however need to be redesigned before they can be correctly interpreted by members of the Nigerian public.