New Tool Reliably Measures How Much THC People Actually Consume
The Cannabis Exposure Inventory (CEI) demonstrated substantial test-retest reliability for measuring milligrams of THC consumed per using day, filling a critical gap in cannabis research that has historically measured only frequency, not quantity.
Quick Facts
What This Study Found
The self-administered CEI showed substantial overall reliability for mean mgTHC/using day (ICC=0.77), with consistent performance across demographic subgroups (ICCs 0.54-0.86), use motivations (ICCs 0.69-0.77), and state legalization contexts (ICCs 0.70-0.92).
Key Numbers
N=511; overall ICC=0.77; Hispanic ICC=0.86; 'other' race ICC=0.54; medical-only ICC=0.72; recreational-only ICC=0.69; medical+recreational ICC=0.77; binary measures mean kappa=0.74 (30-day), 0.73 (7-day)
How They Did This
Test-retest reliability study of 511 participants recruited through social media and research panels, completing initial and retest CEI surveys measuring THC milligrams per using day, with Intraclass Correlation Coefficients and kappa statistics for binary measures.
Why This Research Matters
For decades, cannabis research has measured 'how often' but not 'how much' — this validated tool allows researchers and clinicians to quantify actual THC exposure, which is essential for understanding dose-response relationships.
The Bigger Picture
As cannabis products become more varied and potent, having a reliable self-report measure of THC quantity consumed is essential for advancing our understanding of cannabis benefits and harms.
What This Study Doesn't Tell Us
Self-report measure subject to recall bias; online recruitment may not represent all users; THC content estimates depend on product labeling accuracy; moderate ICC in some subgroups; does not capture other cannabinoids.
Questions This Raises
- ?Would the CEI perform as well in clinical settings?
- ?How does self-reported THC exposure compare to biomarker-based measures?
- ?Can this tool be adapted to measure CBD and other cannabinoid exposure?
Trust & Context
- Key Stat:
- Evidence Grade:
- Well-designed reliability study with adequate sample size and comprehensive subgroup analyses, establishing the psychometric foundation for a needed measurement tool.
- Study Age:
- Published 2026; addresses a long-standing measurement gap in cannabis research.
- Original Title:
- Test-retest reliability of mgTHC consumption in the self-administered Cannabis Exposure Index (CEI).
- Published In:
- Drug and alcohol dependence, 279, 113028 (2026)
- Authors:
- Hasin, Deborah S(31), Borodovsky, Jacob(3), Wall, Melanie(6), Habib, Mohammad I, Murphy, Eilis, Liu, Jun, Stohl, Malki, Struble, Cara A, Livne, Ofir, Greenstein, Eliana, Aharonovich, Efrat, Wisell, Caroline G, Budney, Alan J
- Database ID:
- RTHC-08325
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
How can we measure how much THC someone uses?
The Cannabis Exposure Inventory (CEI) is a new self-report tool that calculates milligrams of THC per using day by accounting for different products, methods, and frequencies — showing substantial reliability (ICC=0.77) in testing.
Why does measuring THC quantity matter?
Most cannabis research only asks how often people use, not how much THC they consume. Since products range from low-potency to extremely concentrated, frequency alone can't capture actual exposure — which is key to understanding health effects.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-08325APA
Hasin, Deborah S; Borodovsky, Jacob; Wall, Melanie; Habib, Mohammad I; Murphy, Eilis; Liu, Jun; Stohl, Malki; Struble, Cara A; Livne, Ofir; Greenstein, Eliana; Aharonovich, Efrat; Wisell, Caroline G; Budney, Alan J. (2026). Test-retest reliability of mgTHC consumption in the self-administered Cannabis Exposure Index (CEI).. Drug and alcohol dependence, 279, 113028. https://doi.org/10.1016/j.drugalcdep.2026.113028
MLA
Hasin, Deborah S, et al. "Test-retest reliability of mgTHC consumption in the self-administered Cannabis Exposure Index (CEI).." Drug and alcohol dependence, 2026. https://doi.org/10.1016/j.drugalcdep.2026.113028
RethinkTHC
RethinkTHC Research Database. "Test-retest reliability of mgTHC consumption in the self-adm..." RTHC-08325. Retrieved from https://rethinkthc.com/research/hasin-2026-testretest-reliability-of-mgthc
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.