Preventing Prescription Stimulant Diversion and Medication Misuse Via a Web-Based Simulation Intervention: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Preventing Prescription Stimulant Diversion and Medication Misuse Via a Web-Based Simulation Intervention (NCT04885166), a randomized na study. The primary outcome is Frequency of Prescription Stimulant Diversion.

2. Clinical Question

This question focuses on a self-reported behavior rather than a clinical diagnosis or a measure of medication supply. The outcome is the mean number of times participants report diversion. It is intended to capture how often the behavior occurs across the stated assessment occasions. The registry also identifies related topics, including confidence in resisting diversion, use of resistance strategies, perceived norms and risks, and communication with prescribers.

The comparison is randomized, but the record does not report numerical primary-outcome estimates or a treatment-effect estimate. It therefore does not establish from the registry information alone whether the groups differed, how large any difference was, or how precisely it was estimated. The registry record also does not report the specific statistical test used to answer this question.

3. Trial Design

The registry describes a randomized, single-masked, parallel-group trial with a completed status. It lists Trinity College as the sponsor, phase as NA, and enrollment as 249. The study summary describes the investigation as multi-site and frames its purpose as examining the preliminary efficacy and feasibility of a computer-based simulation intervention against a placebo condition. The summary refers to 300 college-attending adults with current stimulant prescriptions as the planned study population, while the registry enrollment field records 249.

Participants were assigned to one of two conditions: a web-based simulation intervention or a placebo condition. In the intervention condition, participants receive education about stimulant diversion and misuse and practice responding to medication requests with a virtual human. In the placebo condition, participants learn about psychological conditions affecting college students, their causes, and treatments. The study summary describes a single intervention session with two booster sessions.

The primary outcome is the mean number of times participants report diverting prescribed stimulant medication. The registry lists baseline, 3-months, and 6-months as the outcome time frame. It notes that one fewer participant in the placebo group responded to the 6-month follow-up survey than to the 3-month survey. No complete participant flow, group-specific follow-up counts for the primary outcome, or analysis-population definitions are reported in the registry record.

The listed secondary outcomes concern self-efficacy to resist diversion, resistance strategy use, perceived norms for diversion and misuse, perceived risks, and communication with a prescriber. The record lists 21 outcome measures and 27 analyses. It does not report the masking procedure in operational detail, allocation concealment, the randomization method, or the statistical analysis plan. Randomization describes how participants are assigned; it does not by itself reveal how outcomes were analyzed or whether missing observations were handled appropriately.

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.

Overall Study

Analysis population for the primary outcome, as defined in the registry: There was one fewer participant in the placebo group who responded to the 6-month follow-up survey compared to the 3-month survey.

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.

6. Primary Endpoint

The registry lists the primary outcome as Frequency of Prescription Stimulant Diversion, measured over baseline, 3-months, 6-months.

The primary endpoint is the frequency of prescription stimulant diversion, expressed as the mean number of times participants report having diverted their prescribed medication. The registry defines diversion as giving away, selling, or trading one's medication. The outcome is recorded at baseline, 3-months, and 6-months.

A count of reported occasions gives a direct measure of how often participants say the behavior occurred during the assessment period. Reporting a mean summarizes the average frequency in a group, while the standard deviation describes how spread out individual observations are around that average. This kind of endpoint can distinguish a group with mostly low reported frequency from one with more frequent reported behavior, but the mean alone does not show the distribution of responses or whether a small number of high values influence the average.

Repeated measurements can describe whether reported frequency changes over follow-up and whether the pattern differs between randomized groups. Those comparisons require a specified analysis that accounts for the assessment occasions and any missing observations. The registry record does not report the actual primary-outcome means, standard deviations, group contrasts, confidence intervals, or p-values. It therefore does not permit a quantitative conclusion about the direction, size, or precision of a difference in this endpoint.

The endpoint is a self-reported behavior, not an objective count independently verified by another source. Its interpretation depends on participants understanding the question and accurately recalling and reporting their behavior. The record does not describe a validation procedure for these reports.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Interpreting a randomized trial requires separating its design, outcome definition, analysis, and uncertainty. The registry record supplies information about some design and outcome features, but does not report the primary-outcome estimates or a full statistical analysis plan. General statistical explanations below describe what common quantities mean; they are not claims about methods used in this trial unless stated in the registry record.

What does randomization contribute?

Randomization assigns participants to study conditions by chance. In general, it aims to make the groups comparable, on average, with respect to measured and unmeasured characteristics at the time of assignment. It does not guarantee that groups are identical, and it does not resolve issues that arise after assignment, such as missing follow-up information or differences in how outcomes are measured. The record identifies the allocation as randomized, but the method used to generate or conceal assignments is not reported in the registry record.

A parallel-group design compares participants assigned to one condition with participants assigned to another. In this trial, the conditions are the simulation intervention and the placebo presentation. Single masking means the registry identifies the study as single-masked, but it does not explain who was masked or how masking was maintained. Those details matter when considering whether expectations could influence participant reporting or study conduct.

What do the mean and standard deviation describe?

The primary endpoint is continuous in the registry classification and is summarized as a mean with a standard deviation. In general, a mean is the arithmetic average of observed values. It can provide a compact description of typical frequency, but it may not represent most participants when observations are highly uneven. A standard deviation describes how dispersed observations are around the mean. A larger spread means individual reports vary more; it is not the same as uncertainty in the estimated mean.

The outcome itself is a number of reported diversion occasions, so it has count-like characteristics. Count outcomes can have many low or zero values and a smaller number of larger values. In general, when variability exceeds what a simple statistical model expects, over-dispersion may matter: standard errors and confidence intervals from an unsuitable model can be misleading. The registry does not report the distribution of the outcome or the model used, so it is not possible to determine whether over-dispersion was assessed or how it was handled.

How should repeated assessments be considered?

Measurements at baseline, 3-months, and 6-months are repeated observations for participants who respond at multiple occasions. In general, measurements from the same person tend to be related, so an analysis should account for that dependence if it combines multiple occasions. Possible analytical approaches differ in their assumptions and in the question they answer, such as estimating a group contrast at a particular follow-up or comparing patterns over time. The registry record does not identify the approach used, the specific primary contrast, or whether baseline values were incorporated in the model.

A baseline measurement can describe the groups before follow-up and can sometimes improve precision when used in an appropriate analysis. However, no baseline group values or adjustment method are reported in the registry record. It would not be appropriate to assume that baseline adjustment was or was not performed.

What would uncertainty estimates communicate?

In general, a confidence interval gives a range of values compatible with the data and the assumptions of the analysis. Its width conveys precision: a narrower interval indicates less statistical uncertainty than a wider one. A p-value, in general, describes how incompatible the observed data are with a specified null hypothesis under a statistical model. Neither quantity gives the probability that a treatment works, and neither substitutes for considering the size and relevance of the estimated effect.

No primary-outcome confidence interval, p-value, or group contrast is reported in the registry record. Thus, these concepts explain how results could be interpreted, but they cannot be applied to a numerical trial estimate. The record also does not report a prespecified significance threshold for the primary analysis.

What does the planning illustration mean?

The registry describes a sample-size planning illustration based on a fraction of the observed effect, a two-sided significance level of 0.05, equal allocation, and a normal approximation. Such calculations are general planning tools: they estimate the number of participants per arm needed to detect an assumed effect under stated assumptions. They do not describe the number actually analyzed, do not establish the trial's original design justification, and are not observed power. The record does not report the trial's own sample-size justification. No planning values for particular effect fractions are included in the registry entries used for this explanation.

Planning calculations based on an observed effect are especially dependent on the estimate used as the assumption. An observed estimate can be uncertain, and a smaller assumed effect generally requires more participants for the same target power. This is a general principle, not a reported finding about this trial. The stated illustration should be read as prospective-style planning arithmetic based on an effect assumption, not as evidence that the trial had a particular probability of detecting an effect after its results were observed.

How do safety counts differ from efficacy estimates?

Adverse-event entries are counts of reported events or participants affected, depending on the registry field. They are not the primary diversion endpoint and should not be combined with efficacy outcomes. General interpretation of safety counts considers the number at risk, the event definition, severity, timing, and possible relation to the intervention. The registry reports counts of participants affected by serious events, other events, and deaths by group, but gives no detailed clinical descriptions for the serious-event labels. Sparse event counts can be difficult to compare, and the record does not provide an inferential safety analysis.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome assessed at baseline, 3-months, and 6-months, as well as 21 outcome measures and 27 analyses. Considering several outcomes, time points, or contrasts can raise multiplicity concerns: the more statistical comparisons made, the greater the chance that at least one appears noteworthy by chance if each is interpreted separately. Whether that concern is addressed depends on the prespecified analysis plan and any adjustment or hierarchy of outcomes. The registry record does not report a multiplicity strategy, identify a single primary time-point contrast, or explain how the listed analyses relate to one another.

The primary outcome is not reduced to one comparison in the registry description because it has several time points. No numerical outcome results or complete analysis output are reported in the registry record. Therefore, the direction and uncertainty of results across assessment occasions cannot be reviewed, nor can it be determined whether analyses were selected or adjusted after examining results.

For missing data, the record notes that one fewer participant in the placebo group responded to the 6-month follow-up survey than to the 3-month survey. It does not provide reasons for nonresponse, missingness by outcome, handling of partially observed follow-up, or sensitivity analyses. It also does not state whether the primary analysis included all randomized participants, only participants with observed outcome data, or another analysis population. Those details are important because an analysis of respondents may differ from an analysis that accounts for missing data under explicit assumptions.

The reported follow-up note does not by itself establish the amount or impact of missing primary-outcome data. No missing-data method, such as imputation or a model-based approach, is reported in the registry record. Consequently, the extent to which missing observations could affect estimates cannot be assessed from the information recorded.

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.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: adverse event #1 (0.9%), adverse event #2 (0.9%).

The registry reports serious adverse events among 0 of 122 participants at risk in the web-based simulation intervention group and 2 of 113 participants at risk in the placebo group. It reports 0 other adverse events in each group and 0 deaths in each group. The listed serious-event terms are “Adverse Event #1” and “Adverse Event #2,” each reported as 0.9%; these labels do not identify the clinical nature of the events.

These are descriptive registry counts. They do not establish that the intervention caused or prevented an event, and the absence of a recorded event in one group does not establish absence of risk. The number at risk is the denominator associated with the registry safety reporting, not necessarily the number contributing data to the primary endpoint at every follow-up. The record does not report event timing, severity details beyond the serious-event classification, relatedness to study participation, or a statistical comparison of safety outcomes.

With only the generic event labels and counts available, a detailed clinical safety interpretation is not possible. The counts should be read separately from the primary self-reported diversion outcome and not as a measure of intervention efficacy.

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

The record describes a randomized comparison intended to evaluate a web-based simulation intervention against a placebo presentation for college-attending adults with current stimulant prescriptions. It identifies the primary outcome as mean self-reported frequency of prescription stimulant diversion across baseline, 3-months, and 6-months. That information clarifies what the trial set out to measure and how the two conditions differ.

The registry information does not include numerical primary-outcome results. It therefore does not show whether reported diversion frequency was higher or lower in either condition, whether it changed over time, or how large or precise any group difference might be. No effect estimate, confidence interval, or primary-outcome p-value is reported. A conclusion that the intervention did or did not change diversion would go beyond the information in the registry record.

The listed secondary outcomes cover related perceptions and behaviors, including self-efficacy, resistance strategies, perceived norms and risks, and communication with prescribers. Their presence indicates a broader set of questions, but numerical results are not reported in the registry record for this analysis. The record also lists serious adverse-event counts, but the generic event labels and lack of detailed clinical context limit their interpretation.

Even when results are available, a statistically estimated difference is not automatically a measure of practical importance. In general, the interpretation of an effect should consider its size, uncertainty, outcome measurement, follow-up, and relevance to the study question. Here, the absence of primary numerical results means those considerations cannot be applied to a trial-specific estimate.

The registry record also does not document the full analysis plan, missing-data approach, multiplicity strategy, or analysis populations. Those omissions limit assessment of how robust a reported comparison would be and how the primary question was operationalized. The record supports a description of the design and planned measure, but not a conclusion about efficacy or feasibility.

13. Why This Trial Matters Statistically

This trial raises a statistically useful question about measuring behavior over time. Diversion is defined as giving away, selling, or trading prescribed stimulant medication, and the primary outcome asks participants to report how many times they engaged in it. A count-based self-report outcome can capture frequency, but its distribution may be uneven and its accuracy depends on recall and disclosure. Those measurement features influence the choice and interpretation of statistical summaries.

The design also places the outcome at multiple assessment occasions. Repeated measures can provide information about the course of an outcome rather than a single snapshot, but they require clear specification of the comparison of interest and appropriate handling of within-participant dependence. The registry record identifies the assessment schedule without reporting the model or the primary contrast. This distinction is important: an outcome schedule is not itself an analysis plan.

The listed outcome and analysis counts make multiplicity relevant to interpretation. When several outcomes and time points are examined, readers need to know which findings were prespecified and how the analysis distinguishes confirmatory questions from exploratory ones. The registry record does not report that strategy. Likewise, the noted follow-up response difference makes missing-data handling relevant, but no method or sensitivity analysis is reported.

Finally, the study illustrates why a trial's design description and its results must be read separately. Randomization and a clearly stated endpoint describe how a comparison is intended to work; they do not reveal the estimated effect. Without numerical primary results and uncertainty estimates, the registry entry cannot answer whether the groups differed. This is a limitation of the recorded information, not a statistical finding about the intervention.

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 main limitation for statistical interpretation is that the registry information does not include numerical results for the primary endpoint. Group means, standard deviations, between-group estimates, confidence intervals, and p-values are not reported. Consequently, the size, direction, and precision of the primary comparison cannot be evaluated.

The primary measure is self-reported frequency of diversion. The record does not describe how the questions were administered, the recall period, validation against another source, or procedures intended to reduce reporting error. As a general limitation, recall and willingness to disclose can affect self-reported behaviors, although the extent of any such effect in this study is not reported.

Outcome assessment is listed at baseline, 3-months, and 6-months, but the analysis model, target contrast, and use of baseline values are not reported. The record notes one fewer placebo participant responded at 6-months than at 3-months, but does not report the reasons, overall missingness by outcome, missing-data methods, or sensitivity analyses. The analysis population is also not reported.

The registry lists 21 outcome measures and 27 analyses without describing a multiplicity plan or identifying how confirmatory analyses were distinguished from other analyses. Randomization is reported, but the randomization procedure, allocation concealment, masking details, and statistical analysis plan are not reported in the registry record. These omissions prevent a full appraisal of analysis choices and their assumptions.

The registry summary describes a planned study of 300 participants, whereas the enrollment field records 249. The record does not explain the difference. Safety descriptions are also limited: serious-event labels are generic, and timing, clinical details, relatedness, and inferential comparisons are not reported. These limitations constrain interpretation of both efficacy and safety information.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Preventing Prescription Stimulant Diversion and Medication Misuse Via a Web-Based Simulation Intervention — NCT04885166.
• Registry record last updated 2026-04-08; status last verified 2026-02.
• Results first posted 2026-04-08.
• 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

The registry record describes a completed, randomized, single-masked, parallel-group study sponsored by Trinity College, with enrollment of 249 and phase listed as NA. The study compares a web-based simulation intervention with a web-based placebo presentation in college-attending adults with current stimulant prescriptions. The study summary describes a single session with two booster sessions and a multi-site investigation.

The primary outcome is mean self-reported frequency of prescription stimulant diversion, assessed at baseline, 3-months, and 6-months. Listed secondary outcomes concern resistance self-efficacy and strategies, perceived norms and risks, and prescriber communication. The registry lists 21 outcome measures and 27 analyses.

Numerical primary-outcome estimates and the detailed statistical analysis plan are not reported in the registry record. Safety entries include serious events in the placebo group, no serious events in the intervention group, and no deaths in either group; the serious-event terms are generic. The record notes one fewer placebo participant responded at 6-months than at 3-months.