Feasibility and Acceptability of the Cannabis Awareness and Prevention Toolkit: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Feasibility and Acceptability of the Cannabis Awareness and Prevention Toolkit (NCT05521321), a randomized na study. The primary outcome is Cannabis Use (Lifetime).

2. Clinical Question

The study’s stated aim is to investigate whether the curriculum changes students’ intentions to use cannabis and their actual use. The named primary outcome is narrower: lifetime cannabis use, assessed by investigator-originated survey questions. The registry record also lists cannabis knowledge and perceptions of the addictiveness and harmfulness of smoked cannabis, vaped cannabis, and cannabis edibles among the secondary outcomes.

Because lifetime use is measured at baseline and at two later assessments, interpretation depends on the results at each time and on the analysis used to compare groups or changes over time. A count at one assessment does not by itself show whether the curriculum changed new use, intentions, or perceptions. Those outcomes require their own measures and analyses. Results for these questions are not reported in the registry record.

3. Trial Design

The registry describes a completed, randomized, parallel-group behavioral study sponsored by Stanford University. Allocation is recorded as randomized, and masking is recorded as none. The record lists an enrollment of 658. It does not explain the randomization procedure, whether allocation was concealed, or how the enrollment figure relates to the number of students responding at each assessment.

One group received the Stanford Smart Talk Cannabis Prevention and Awareness curriculum. The comparator group received another curriculum or no cannabis prevention curriculum. The curriculum description refers to five lessons and materials intended to address factors associated with youth cannabis use, including attitudes and misperceptions, responses to marketing and social media, stress and depression, coping skills, intentions, and use. These are the curriculum’s stated aims; they are not evidence that any of these factors changed.

The primary outcome is lifetime cannabis use, measured at baseline, post-intervention, and 6-month follow-up. The post-intervention assessment is described as occurring approximately 3 days post-baseline. The record says the primary-outcome population consists of middle-school students who received their allocated intervention and responded to the survey at the respective time points. It does not specify how many students contributed data at each assessment.

The study start date is 2022-10-01, and the primary completion date is 2025-05-16. Its status is completed. The record lists phase as NA, which is consistent with the behavioral intervention description rather than a drug-development phase. Details of the participating schools, the number of schools, the unit of randomization, and any school-level design features are not reported in the registry record. These omissions matter because students in the same school may share experiences, and the analysis may need to account for the design actually used.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: 19 schools were assessed for eligibility. 11 were randomized to intervention or standard of care. Educators were considered to be enrolled only at those schools that received the intervention (they delivered the intervention to the students, and participated in post-intervention qualitative interviews focused on quality assurance and quality improvement).

Overall Study

Analysis population for the primary outcome, as defined in the registry: Students from middle schools who received the allocated intervention and responded to the survey at the respective time points.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Population: Students who received the allocated intervention and completed the baseline survey were included in the analysis. Educators at schools that received the intervention who participated in post-intervention qualitative interviews did not complete study surveys for baseline characteristics; no baseline data were collected from them so they are not included in the analysis.

6. Primary Endpoint

The registry lists the primary outcome as Cannabis Use (Lifetime), measured over Baseline, Post-intervention (approx. 3 days post-baseline), and 6-month Follow-up.

The primary endpoint is the count of participants reporting lifetime cannabis use. The registry describes it as assessed through investigator-originated survey questions and specifies middle-school students who received their allocated intervention and responded at each relevant time point. Assessments were scheduled at baseline, post-intervention, approximately 3 days post-baseline, and at 6-month follow-up.

A lifetime-use measure records whether a participant reports ever having used cannabis by the time of the survey. It can describe the prevalence of reported lifetime use in the responding group at an assessment. By itself, it does not identify when use began, how often it occurred, or whether use happened during the period after the intervention. Those details are not part of the endpoint description in the registry record.

Repeated assessment can help describe outcome patterns across time, including the starting point and later observations. For a randomized study, a comparison between groups is generally needed to distinguish a pattern associated with assignment from changes that might occur in both groups. This is a general statistical principle; the registry record does not report a primary comparison, effect estimate, confidence interval, or test result.

The measure is used as the primary endpoint because the study aims to examine students’ actual cannabis use as well as intentions. However, the specific endpoint reported is lifetime use, not a distinct measure of intentions. The intention outcome’s measurement and results are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The study is described as randomized and parallel-group. In general, random allocation is intended to make groups comparable at the start with respect to both measured and unmeasured characteristics, on average. A parallel design assigns participants to a group that receives the intervention or comparator, with groups followed over the same study period. The registry record does not describe the randomization method, allocation concealment, or whether randomization was carried out at the student or school level.

Masking is recorded as none. In general, masking means keeping participants, investigators, or outcome assessors unaware of assigned group, where feasible. A lack of masking may matter especially for self-reported outcomes, since expectations or awareness can influence reporting. This is a general methodological consideration; the registry record does not say whether survey administration or data analysis was blinded.

The primary outcome is a participant count for lifetime cannabis use, a binary-type outcome in the record’s outcome classification. For a binary outcome, each participant is classified according to whether the event or characteristic is present, and a group count is the number classified as present. Counts alone are not enough to compare groups unless the corresponding numbers assessed are also known. The registry record does not report the primary-outcome counts or denominators at the specified assessments.

Repeated measurements create more than one possible statistical contrast. A comparison at follow-up asks how the groups differ at that assessment. A change comparison asks how each group’s outcome changed from baseline and then compares those changes. A model using all assessments can address the pattern over time, subject to its assumptions. These are general approaches; the analysis selected for this study is not reported in the registry record. The registry’s note that the primary outcome has several categories or time points and was not reduced to one comparison reinforces that no single contrast is available to interpret from the record.

For any estimated contrast, a confidence interval is a general way to express the precision of an estimate. It gives a range of values compatible with the data and the method’s assumptions; a wider interval indicates greater uncertainty than a narrower one. The registry record reports no confidence interval for the primary outcome. Without an estimate and its uncertainty, the magnitude and precision of a possible group difference cannot be assessed.

Statistical significance and practical importance are different concepts. In general, a p-value describes how compatible observed data are with a specified statistical model under a null hypothesis; it is not the probability that the null hypothesis is true and does not quantify the size of an effect. An effect estimate and its uncertainty are needed to discuss magnitude. No primary-outcome p-value or effect estimate is reported in the registry record, so neither statistical significance nor the size of a difference can be evaluated from it.

The record notes planning illustrations computed from an observed effect, with a two-sided significance level of 0.05, equal allocation between groups, and a normal approximation; the effect to detect is a stated fraction of the observed effect. These are planning assumptions, not evidence about outcomes. A sample-size illustration is not observed power, and it should not be read as a justification for the original study design. The trial’s own sample-size justification is not reported in the registry record. No calculated planning values are reported in the information available for this interpretation.

General statistical planning also depends on the outcome type, expected event frequency, the contrast of interest, and features of the design. If participants are grouped within schools, for example, responses from students in the same school may be correlated. Such correlation can reduce the amount of independent information in the data; methods that assume every response is independent may then give uncertainty estimates that are too small. Whether students were randomized by school or analyzed with school clustering is not reported in the registry record, so no claim can be made about how this design issue was handled.

The registry lists nine outcome measures and names secondary outcomes concerning cannabis knowledge and perceptions of the addictiveness and harmfulness of smoked cannabis, vaped cannabis, and cannabis edibles. When multiple outcomes or time points are tested, the chance of at least one apparently unusual result can rise if each is treated as a separate confirmatory test. General approaches to this issue include prespecifying a primary contrast or adjusting inference across multiple tests. The registry record does not describe a multiplicity strategy or identify a single primary comparison across the listed time points.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists nine outcome measures, including the primary lifetime cannabis-use measure and named secondary outcomes for cannabis knowledge and perceptions of the addictiveness and harmfulness of smoked cannabis, vaped cannabis, and cannabis edibles. The primary outcome itself is scheduled at baseline, post-intervention, and 6-month follow-up. Multiple outcomes and assessments can create multiple opportunities to find a result that appears noteworthy by chance. In general, a statistical plan can address this by defining a primary contrast in advance, limiting confirmatory tests, or adjusting inference across tests. The approach used in this study is not reported in the registry record.

The record does not report a single primary comparison across the outcome’s time points. It also does not provide analysis results, a statistical analysis plan, or whether secondary outcomes were treated as confirmatory or exploratory. The number of analyses listed is 0; no analysis results are available in the registry record.

Missing-data handling is not reported in the registry record. The primary-outcome population is described as students who received the allocated intervention and responded at the relevant time point, but the record does not state the number of responders at each assessment, the number missing, or how missing survey responses were handled. It does not describe imputation, sensitivity analyses, or reasons for nonresponse.

The analysis population is also not fully specified. The outcome description focuses on allocated-intervention recipients who responded, but the registry record does not say whether the main analysis included all randomized participants, only participants with observed responses, or another defined group. These distinctions matter because exclusions and loss to follow-up can affect comparability. The available record does not permit evaluation of their impact.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The adverse-event record reports 0 serious adverse events among 419 participants at risk in the group receiving the Stanford curriculum and 0 among 239 participants at risk in the group not receiving it. It also reports 0 other adverse events in each group and 0 deaths in each group. No serious adverse-event terms are listed.

These are reported counts for the safety record, not primary-outcome results. A zero count means no events of the listed type were recorded in the stated group denominator in this registry entry. It does not establish that an event could not occur, that all events were captured, or that the groups have identical underlying event risks. The record does not describe the safety-monitoring procedures, event definitions, reporting window, or whether all participants contributed the same observation time.

The safety denominators should not be substituted for the numbers of students who completed the lifetime-use surveys. Those survey response counts are not reported in the registry record. The adverse-event figures therefore describe only the safety information recorded, and they do not resolve the study’s primary question about lifetime cannabis use.

12. What the Result Does, and Does Not, Mean

The registry record establishes that a randomized, parallel-group behavioral study was completed and identifies its intervention, comparator, population, and primary outcome schedule. It also reports safety counts. However, the record does not report the lifetime cannabis-use results, the secondary-outcome results, or the analyses needed to compare the groups. The existence of a completed trial and a stated curriculum aim does not show whether an outcome changed.

The primary measure concerns reported lifetime use. It does not, by itself, specify when use began or measure frequency, and it is not the same as an intention-to-use measure. The study’s summary mentions both intentions and actual use as aims, but the registry’s named primary endpoint is lifetime cannabis use. An effect on one measure would not automatically demonstrate an effect on the other.

The three assessment times could support several distinct questions: how groups compare at a particular assessment, whether their changes from baseline differ, or whether their patterns across assessments differ. Those questions can produce different estimates and require a defined analysis. The registry record does not identify a selected primary contrast or report a result for any of these questions.

General statistical interpretation requires considering both the estimated magnitude and its uncertainty, along with the outcome definition and the participants contributing data. Here, no primary-outcome estimate, confidence interval, or p-value is reported. Therefore, neither the direction nor precision of a group difference can be described. The enrollment figure does not supply that missing information, and the safety denominators do not stand in for survey response totals.

The record also does not report how missing survey data, multiple outcomes, or the analysis population were handled. These are relevant to judging whether a reported comparison would be robust, but the available record does not permit that assessment. No conclusion about the curriculum’s effects on cannabis use, intentions, knowledge, or perceptions follows from the information recorded.

13. Why This Trial Matters Statistically

This trial raises several statistical questions that are important when evaluating behavioral interventions with self-reported outcomes. The study compares a curriculum with another curriculum or no cannabis prevention curriculum, while assessing a lifetime-use outcome repeatedly. Interpreting such a design requires knowing not only the outcome values, but also which comparison was intended and how responses from each assessment were analyzed.

The primary outcome is recorded at baseline, shortly after baseline, and at 6-month follow-up. Repeated time points can show whether group patterns are stable or change, but they also create choices about the main contrast. A follow-up comparison and a comparison of change from baseline are not interchangeable. The registry record does not specify a single primary contrast, and that makes it important not to treat any one time point as the definitive result without an analysis plan.

The design is described as randomized, but details of randomization and the role of schools are not reported. In general, if assignment or shared context operates at the school level, analysis may need to account for dependence among students from the same school. This is a design consideration, not a claim about the procedures used in this study. The registry record does not clarify the unit of randomization or the statistical handling of clustering.

The registry also names several secondary outcomes and multiple assessments. A clear distinction between confirmatory and exploratory analyses can help readers understand how to interpret findings across many outcomes. The multiplicity approach is not reported. Further, the endpoint is survey-based, so response rates and missing-data handling are relevant to interpreting the observed population; those details are also not reported.

These issues do not establish a flaw in the study. They identify information needed to judge the strength and precision of any comparison. As recorded, the trial offers a defined question and design, but not the outcome estimates or analysis details needed for statistical evaluation of its results.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The registry record does not report primary-outcome counts at baseline, post-intervention, or 6-month follow-up, nor does it report an effect estimate, confidence interval, or p-value. This prevents assessment of the direction, magnitude, and precision of the principal comparison.

The outcome is described as lifetime cannabis use, measured by investigator-originated survey questions. The record does not provide the exact questions, response options, validation information, or details on survey administration. It also does not report the intention measure mentioned in the study aim. The scope of what can be interpreted is therefore limited to the endpoint description, not a detailed assessment of measurement quality.

The analysis population and response totals at each time point are not reported. Although the outcome description refers to students who received the allocated intervention and responded, it does not specify how nonresponders or participants with incomplete assessments were handled. Missing-data methods and sensitivity analyses are not reported in the registry record.

The record does not state the unit of randomization, the number of schools, or whether analyses accounted for students clustered within schools. It also does not describe the allocation procedure, concealment, or any blinding of survey administration or analysis. These are unknowns in the registry record, not evidence that particular methods were or were not used.

Finally, the registry does not describe a statistical analysis plan, a single primary contrast across the three assessment times, or a strategy for handling multiple outcomes and time points. The trial’s own sample-size justification is not reported. These gaps limit the conclusions that can be drawn from the registry entry, even though it identifies the study as completed and records its enrollment and safety counts.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Feasibility and Acceptability of the Cannabis Awareness and Prevention Toolkit — NCT05521321.
• Registry record last updated 2026-07-28; status last verified 2026-06.
• Results first posted 2026-07-28.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

NCT05521321 is a completed, randomized, parallel-group behavioral study sponsored by Stanford University. The registry records enrollment of 658 and no masking. One group received the Stanford Smart Talk Cannabis Prevention and Awareness curriculum; the comparator received another curriculum or no cannabis prevention curriculum.

The primary outcome is the count of participants reporting lifetime cannabis use, assessed at baseline, post-intervention approximately 3 days post-baseline, and 6-month follow-up. The record also lists secondary outcomes concerning cannabis knowledge and perceptions of the addictiveness and harmfulness of smoked cannabis, vaped cannabis, and cannabis edibles.

The registry reports 0 serious adverse events, 0 other adverse events, and 0 deaths in each recorded group. Primary and secondary outcome results, analysis details, missing-data handling, and the trial’s sample-size justification are not reported in the registry record.