Online Methods for Locating Medical Marijuana Dispensaries: Practical Considerations for Future Research.

Knowing the names, locations, and signage of medical marijuana dispensaries is critical for assessing how marijuana availability affects neighborhood quality and marijuana use, yet no detailed methods for locating and coding dispensaries are published. Limitations regarding accuracy of official records, unregulated businesses, and the size of areas where dispensaries are located make it difficult to accurately capture all open dispensaries in any area. In this study, we test a practical and feasible method to collect a point-in-time portrayal of medical marijuana dispensaries in a large urban area lacking an official record of these businesses. Using publicly-available Internet sources alone, we collected the name, address, phone number, signage, and open/closed status of medical marijuana dispensaries in Los Angeles County between October 2016 and February 2017. Data were verified by calling a subset of dispensaries and comparing data against a list of licensed dispensaries. Our methods yielded 872 unique dispensaries in Los Angeles County, of which 470 were open. Most open stores were discernable by a green cross sign; however, few had names that clearly indicated the store sold marijuana. Data verification procedures showed that Internet sources were able to locate nearly all dispensaries in the county that were then verified with non-Internet methods, such as calling the businesses to confirm information. This study is significant as it provides methodology that can be replicated in other metropolitan areas, facilitating comparisons across databases in different locations and regulatory environments. However, caution should be taken when solely using Internet sources. Accurate information on dispensary names, locations, and signage can advance research and provide important information for policy decisions. Methods for enhancing the online methods described in this study are discussed.