Surveying Patients at Marijuana Dispensaries Produces Representative Data With Minimal Bias
Researchers found that conducting surveys at medical marijuana dispensaries produced data with minimal selection or respondent bias, validating this as a reliable method for studying medical cannabis patients.
Quick Facts
What This Study Found
Medical marijuana users are a "hidden population" that is difficult to access through traditional survey methods. Researchers from UCLA evaluated whether conducting surveys at dispensaries introduces systematic biases that would undermine the results.
They used a two-stage venue-based sampling approach and tested for two types of bias: selection bias (whether participating dispensaries differed systematically from non-participating ones) and respondent bias (whether patients who completed surveys differed from those who declined).
Both types of bias were generally absent. The dispensaries that participated were representative of dispensaries overall, and the patients who responded were representative of the broader patient population. This validation means that research findings from dispensary-based surveys can be used to inform policy and clinical practice with reasonable confidence.
Key Numbers
Selection bias was generally absent among participating dispensaries. Respondent bias was minimal among survey completers. Results were from the UCLA Medical Marijuana Study in Los Angeles.
How They Did This
The study used the venue-based sampling procedures from the UCLA Medical Marijuana Study, employing a two-stage approach. Statistical analyses compared participating vs non-participating dispensaries and responding vs non-responding patrons on available characteristics.
Why This Research Matters
Reliable data on medical cannabis patients is essential for evidence-based policy. This study validates a practical method for collecting that data, showing that dispensary-based research can produce findings that represent the broader population of medical cannabis users in a given area.
The Bigger Picture
As medical cannabis programs expand, policymakers need reliable data on who uses medical cannabis, why, and with what outcomes. This methodological validation makes the case that dispensary-based surveys are a viable and trustworthy data source.
What This Study Doesn't Tell Us
The study was conducted in Los Angeles, where dispensary culture and patient demographics may differ from other regions. Patients who obtain medical cannabis outside of dispensaries (home growing, online) are not captured. The methodology assumes dispensaries are the primary access point, which may not hold in all jurisdictions.
Questions This Raises
- ?Does this methodology work in states with different dispensary models?
- ?Would online surveys of medical cannabis patients complement dispensary-based approaches?
- ?How should researchers handle states where home cultivation is the primary access method?
Trust & Context
- Key Stat:
- Both selection bias and respondent bias were minimal in dispensary-based surveys of medical cannabis patients.
- Evidence Grade:
- Moderate evidence from a methodological validation study using established statistical approaches to assess bias.
- Study Age:
- Published in 2016. Dispensary-based research has since become common in medical cannabis studies.
- Original Title:
- Assessing Sample Bias among Venue-Based Respondents at Medical Marijuana Dispensaries.
- Published In:
- Journal of psychoactive drugs, 48(1), 56-62 (2016)
- Authors:
- Thomas, Crystal, Freisthler, Bridget(6)
- Database ID:
- RTHC-01280
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
Can we trust research done at dispensaries?
This study found that conducting surveys at medical marijuana dispensaries did not introduce meaningful bias. The results were representative of the broader medical cannabis patient population, validating this research approach.
Why is this important?
Policy decisions about medical cannabis depend on reliable data about who uses it and why. This study shows that the practical method of surveying patients at dispensaries produces trustworthy data that can inform those decisions.
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Cite This Study
https://rethinkthc.com/research/RTHC-01280APA
Thomas, Crystal; Freisthler, Bridget. (2016). Assessing Sample Bias among Venue-Based Respondents at Medical Marijuana Dispensaries.. Journal of psychoactive drugs, 48(1), 56-62. https://doi.org/10.1080/02791072.2015.1127450
MLA
Thomas, Crystal, et al. "Assessing Sample Bias among Venue-Based Respondents at Medical Marijuana Dispensaries.." Journal of psychoactive drugs, 2016. https://doi.org/10.1080/02791072.2015.1127450
RethinkTHC
RethinkTHC Research Database. "Assessing Sample Bias among Venue-Based Respondents at Medic..." RTHC-01280. Retrieved from https://rethinkthc.com/research/thomas-2016-assessing-sample-bias-among
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.