Variation in cannabis potency and prices in a newly legal market: evidence from 30 million cannabis sales in Washington state.
Level 4 - case-series / case-control
Secondary observational analysis of state administrative sales transaction data
PubMed 28556310 · doi:10.1111/add.13886
What was done
Secondary analysis of administrative transaction data from Washington State's cannabis traceability system from July 7, 2014, to September 30, 2016. Descriptive statistics and linear regressions examined product market share and cannabinoid concentrations (THC and CBD). Hedonic price regressions evaluated the association between flower price per gram, potency, and purchase quantity across 31,052,123 cleaned flower purchases from a total of 44,482,176 retail transactions.
What was found
Cannabis flowers accounted for 66.6% of spending, while the market share of inhalation extracts increased by 145.8% between October 2014 and September 2016 to reach 21.2% of sales. Mean THC concentration was 68.7% for extracts and 20.6% for flower. For flower products, higher price per gram was significantly associated with both THC (coefficient = 0.012, 95% CI: 0.011 to 0.013) and CBD (coefficient = 0.017, 95% CI: 0.015 to 0.019). The estimated discount elasticity was -0.06 (95% CI: -0.07 to -0.05).
Why it matters
This study provides empirical population-level data on consumer purchasing patterns following cannabis legalization, demonstrating market expansion toward high-potency extracts alongside price premiums for both THC and CBD concentrations in flower.
Limits
The data represent sales records rather than individual-level consumption, frequency, or health outcomes. Potency metrics relied on administrative traceability data without independent laboratory verification noted in the abstract. Results reflect a single state's market during its early implementation phase and may not generalize across differing regulatory frameworks.