Development of a Scale for Health Product Literacy in Grocery Owners

Abstract

Objective: To develop the Health Products Literacy in Grocery Owners (HPLGO) scale. The secondary objective was to conduct a pilot study to determine the cut-off point of the HPLGO score to predict the chances of grocery stores to 1) sell health products and 2) sell unsafe health products. Method: The study tested the scale developed from a literature review in 63 grocery store owners purposively selected from 4 areas in Mae Hong Son, Lampang and Udon Thani provinces. The appropriate HPLGO cut-off point was determined using the receiving operating characteristics (ROC) curve technique. Results: There were 59 grocery stores (93.7%) that sold health products, of which 41 (65.1%) sold unsafe health products. The developed 29 item HPLGO scale consisted of 6 dimensions including information access, understanding, inquiry interaction, decision-making, behavior modification, and information sharing. The test yielded 23 questions with the possible score range of 23-115. Cronbach's alpha of each dimension of the scale was 0.72-0.92 and of the whole scale was 0.96. When using health product sales as gold standard with a cut-off point of >90 points, the specificity was as high as 100 percent, but the sensitivity was low (44.1 percent, 95%CI 31.8-56.3). The area under the ROC curve was at a fair level (72.0%, 95%CI 0.58-0.86). When using the sales of unsafe health product as gold standard with the cut-off point of >110 points, high specificity was obtained (95.4%, 95%CI 90.3-100.0) but with low sensitivity (19.5%, 95%CI 9.7-29.3). The area under the ROC curve was low (60.0%, 95%CI 0.45-0.75). Conclusion: The developed HPLGO scale has acceptable reliability, is easy to use, and does not take much time to complete. Therefore, it can be used by personnel responsible for consumer protection in the community. However, the cut-off point must be confirmed by testing in a larger sample and expanding areas for data collection.