Aims: To evaluate the feasibility and validity of a new method of quantifying cannabis flower use, integrating the amount of cannabis flower smoked, and the potency of the cannabis flower.Design: Ecological momentary assessment (EMA) for 14 days.

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While there is strong evidence for the psychometric reliability of the Positive and Negative Affect Schedule-Expanded Form (PANAS-X) in cross-sectional studies, the between-and within-person psychometric performance of the PANAS-X in an intensive longitudinal framework is less understood. As affect is thought to be dynamic and responsive to context, this study investigated the multilevel reliability of PANAS-X Positive Affect, Negative Affect, Fear, Sadness, and Hostility scales. Generalizability theory and structural equation modeling techniques (coefficient ω) were employed in four ecological momentary assessment samples (N = 309; 41,261 reports). Results demonstrate that the PANAS-X scales, including short versions of the Positive and Negative Affect scales, can reliably detect between-person differences. PANAS-X scales also were able to reliably measure within-person change, though these estimates may be impacted by scale content and study design. These results support the use of the PANAS-X in daily life research to intensively measure affect in the natural environment. Public Significance StatementThe Positive and Negative Affect Schedule (PANAS-X) is commonly used to measure change in affect from moment to moment in ecological momentary assessment studies, though the PANAS-X was not originally designed with these studies in mind. This study demonstrates that researchers can reliably use the PANAS-X to capture changes in positive affect, negative affect, sadness, hostility, and fear in daily life using ecological momentary assessment.

Objective: This study compares three methods of cannabis and of alcohol use assessment in a sample of regular cannabis users: (a) ecological momentary assessment (EMA) repeated momentary surveys aggregated to the daily level, (b) EMA morning reports (MR) where participants reported on their total use from the previous day, and (c) retrospective timeline followback (TLFB) interviews covering the same period of time as the EMA portion of the study. We assessed the overall correspondence between these methods in terms of cannabis and alcohol use occasions and also investigated predictors of agreement between methods. Method: Forty-nine individuals aged 18-50 (M age = 24.49, 49% female, 84% White) who reported regular cannabis use completed a 14-day EMA study. At the end of the EMA period, participants returned to the laboratory to complete a TLFB (administered via computer) corresponding to the same dates of the EMA period. Results: Daily aggregated EMA and TLFB reports showed a low to modest agreement for both alcohol and cannabis use. Overall, agreement between EMA and MR was better than agreement between EMA and TLFB, likely because less retrospection is required when only reporting on behavior from the previous day. Quantity and frequency of use differentially predicted agreement across reporting methods when assessing alcohol compared to cannabis. When reporting cannabis use, but not alcohol use, individuals who used more demonstrated higher agreement between EMA and TLFB. Conclusions: Results suggest that retrospective reporting methods assessing alcohol and cannabis should not be considered a direct "substitute" for momentary or daily assessments. Public Health Significance StatementThis study highlights the importance of differentiating between in-the-moment and retrospective reports of alcohol and cannabis use.

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