Vaper to Vaper: A Multimodal Mobile Peer Driven Intervention to Support Adolescents in Quitting Vaping: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Vaper to Vaper: A Multimodal Mobile Peer Driven Intervention to Support Adolescents in Quitting Vaping (NCT05140915), a randomized na study. The primary outcome is Participant Recruitment and Retention.

2. Clinical Question

The clinical question therefore concerns whether the study could recruit and retain adolescents in a peer-supported mobile intervention, and how that experience compared with provision of cessation materials. Vaping abstinence was also listed as a secondary outcome, measured using saliva samples for cotinine-validated 7-day point prevalence at 3 months. That outcome addresses a different question from the primary endpoint: whether participants met the specified abstinence definition at follow-up.

The registry record identifies a randomized comparison with schools assigned to intervention or control. It does not give detailed eligibility criteria, the age distribution, or the number of schools in each condition. Those omissions limit how specifically the population and setting can be characterized from the record. The intervention also combines several components, so the comparison evaluates the overall package against cessation materials; it does not isolate the effect of peer messages, coaching, or gamification individually.

3. Trial Design

The registry record describes a randomized, single-masked, parallel-group study, with schools randomized to the intervention or control condition. Enrollment was 71. The intervention group received peer messages, peer coaching by text, and gamification; the control group received e-cigarette cessation materials at enrollment. The registry does not identify who was masked, so the masking designation cannot be interpreted more specifically from this record.

The study is marked completed. Its recorded start date is 2022-12-19, and its primary completion date is 2023-06-09. The primary outcome was assessed at 3 months and concerns the number of screened, eligible, and consented participants who remained active in the program. The posted primary counts are 37 of 39 in the intervention group and 31 of 32 in the control group. These are counts for the registered retention endpoint, not evidence by themselves about vaping cessation.

Secondary outcomes listed in the registry include acceptability and satisfaction, cotinine-validated abstinence, peer-coaching interactions, peer videos viewed, games engaged in, self-efficacy, stage of change, and nicotine-addiction severity. Detailed posted results are available for acceptability and satisfaction, abstinence, and self-efficacy. Results for the other listed outcomes are not reported in the registry record.

The registry lists the study phase as not applicable. It does not report the original sample-size justification, detailed allocation procedures, the masking role, an interim-analysis plan, or a full analysis protocol. These details should not be inferred from the randomized, single-masked, parallel-group labels. The primary endpoint and the available results can be described, but the registry record does not establish how the investigators planned to handle every analysis decision or missing observation.

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

Reasons for not completing this period:

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 Participant Recruitment and Retention, measured over 3 months.

The primary endpoint is participant recruitment and retention. It measures the number of people who were screened, eligible, and consented and who remained active in the program at 3 months. In the posted results, the intervention group has a value of 37 among 39 participants, and the control group has a value of 31 among 32 participants.

This endpoint is useful for assessing whether a study can enroll participants and keep them engaged through follow-up. For an intervention delivered through mobile messaging, coaching, and games, continued participation is relevant to the practical delivery of the program and to the feasibility of collecting later outcomes. Retention also affects how much follow-up information is available for outcomes such as abstinence, self-efficacy, and satisfaction.

Retention is not the same as intervention use, satisfaction, or cessation. A participant can remain active without meeting an abstinence definition, and the endpoint does not indicate how often each intervention component was used. Conversely, a participant’s vaping status cannot be established from the retention count alone. The registry lists cotinine-validated 7-day point-prevalence abstinence as a secondary outcome, with its own follow-up data.

The registry record does not explain the operational definition of “active” beyond the primary outcome description, nor does it specify what activity was required to count as retained. The endpoint should therefore be interpreted according to the posted description rather than as a more detailed measure of engagement or adherence.

7. Results Posted in the Registry

• Intervention: 94.9% (37/39) versus 96.9% (31/32) on control; risk difference -2.0 percentage points (95% CI -11.2 to 7.2), risk ratio 0.98 (0.89–1.08); unadjusted two-proportion z-test p = 0.676.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Acceptability of and Satisfaction With the Intervention

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Intervention: mean 25.34 versus 24.95 on control; difference 0.39 (95% CI -2.20 to 2.98), standardized effect d = 0.08; z-test p = 0.768.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Intervention and the control. The interval gives the range of effects that remain compatible with the data.

Number of Participants With Abstinence From Vaping as Measured by Saliva Samples [Cotinine-validated 7-day Point Prevalence]

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Intervention: 13.9% (5/36) versus 15.6% (5/32) on control; risk difference -1.7 percentage points (95% CI -18.6 to 15.2), risk ratio 0.89 (0.28–2.79); unadjusted two-proportion z-test p = 0.840.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Intervention and the control. The interval gives the range of effects that remain compatible with the data.

Change in Self-Efficacy Score

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Intervention: mean -0.19 versus 0.15 on control; difference -0.34 (95% CI -0.44 to -0.24), standardized effect d = -1.62; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Intervention than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The posted secondary outcomes cover several different aspects of the intervention: participant experience, abstinence, engagement with mobile components, self-efficacy, stage of change, and nicotine-addiction severity. These outcomes are related to the program’s aims, but they are not interchangeable. Engagement and satisfaction describe use or experience, while abstinence and changes in scores address different participant outcomes.

The secondary findings do not form a single consistent test of the primary retention result. The primary endpoint asks whether participants remained active at 3 months; secondary outcomes ask what participants reported or did, and whether abstinence or score changes were observed. A retention result cannot substitute for those outcomes, and a difference in a secondary score does not establish a retention difference. The posted results therefore need to be interpreted according to each endpoint’s definition and measurement scale.

Detailed results are posted for acceptability and satisfaction, cotinine-validated abstinence, and self-efficacy change. The registry lists additional secondary outcomes, including peer-coaching interactions, peer videos viewed, games engaged in, stage of change, and nicotine-addiction severity, but results for these are not reported in the registry record. This leaves the overall pattern of secondary outcomes incomplete.

Unadjusted secondary results generally carry less confirmatory weight when many outcomes are examined. In general, testing several outcomes increases the chance that at least one result will appear statistically unusual by chance, even if there is no corresponding effect. A multiplicity plan can specify how to address that issue, but one is not reported in the registry record. The self-efficacy comparison is therefore a notable unadjusted result, not definitive evidence on its own. Its meaning also depends on the score’s direction, validity, and clinical interpretation, which are not described in the registry entry. Secondary outcomes can inform further questions, but the registry does not establish a prespecified hierarchy or adjustment strategy that would support treating any one as a definitive finding.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Acceptability of and Satisfaction With the Intervention
• Number of Participants With Abstinence From Vaping as Measured by Saliva Samples [Cotinine-validated 7-day Point Prevalence]
• Number of Peer Coaching Interactions
• Number of Peer Videos Viewed
• Number of Games Engaged In
• Change in Self-Efficacy Score
• Number of Participants With With Change in Stage of Change
• Change in Severity of Nicotine Addiction

9. Statistical Interpretation

10. Statistical Methods Explained

The posted comparisons use two broad kinds of summaries. Retention and abstinence are binary outcomes: each participant either meets the stated outcome definition or does not. Acceptability and satisfaction and self-efficacy are continuous scores, summarized by group means and standard deviations. The methods below explain how these summaries are generally interpreted; the registry record does not report a complete statistical analysis plan for the trial.

How should a risk difference be read?

For a binary outcome, the risk in a group is the proportion of participants in that group who meet the outcome definition. A risk difference compares those proportions by subtracting the control-group proportion from the intervention-group proportion. A value near zero indicates similar observed proportions; a positive or negative value indicates the direction of the contrast according to the stated group order. The primary retention comparison is reported as a risk difference of -0.02. The abstinence comparison is also expressed as a risk difference.

A risk difference is an absolute contrast, not a relative one. It keeps the comparison on the scale of the outcome proportions and can be easier to connect to the observed event counts than a ratio measure. The posted summaries also contain relative measures for some binary comparisons, but the interpretation emphasizes the risk difference and its uncertainty. No additional effect measure needs to be calculated to describe the posted results.

What does a confidence interval add?

A confidence interval expresses the range of values reasonably compatible with the observed data under the statistical method used. It describes uncertainty about an estimated group contrast; it is not a range containing a known fixed proportion of individual participant outcomes. When an interval for a difference includes zero, the data do not clearly distinguish a positive contrast from a negative contrast at the confidence level used. That does not prove the groups are equivalent. A sufficiently wide interval can include no difference while also allowing effects that could matter in either direction.

The registry record gives confidence intervals for the recalculated comparisons, but does not state the confidence level for these recalculations in the outcome entries. The sample-size planning assumptions are described separately and should not be treated as a full account of the analysis methods used for the posted outcomes.

How are continuous outcomes compared?

For a continuous score, a mean difference compares the group averages. In the acceptability and satisfaction results, the difference is 0.39 points. In the self-efficacy change results, the difference is -0.34 points. A standard deviation describes variation among scores within a group; it is not the uncertainty interval for the mean or the group contrast. The posted acceptability and satisfaction results include group standard deviations, and the self-efficacy results report standard deviations for change scores.

The registry reports a two-sided t-test for acceptability and satisfaction, with p = .77. A t-test evaluates whether the observed difference is unusual under a statistical model in which the group means are equal. The recalculated unadjusted p-value is 0.768. A p-value is not the probability that the null hypothesis is true, nor does it measure the size or importance of a difference. For self-efficacy, the unadjusted recalculated p-value is <0.001; the registry record does not list a corresponding reported analysis.

Why are the recalculations unadjusted?

The recalculated comparisons use posted group-level summary statistics and do not account for covariates, school-level clustering, or other design features. This is important because schools, rather than individual students, are described as randomized. In general, outcomes from participants within the same school may be correlated. A model that accounts for that correlation can yield uncertainty estimates different from an analysis that treats all participant observations as independent. The registry record does not report whether or how school clustering was incorporated in the trial’s own analyses.

The registry lists randomization and a parallel-group structure, but does not report allocation-concealment details, the identity of masked personnel, a detailed statistical analysis plan, a missing-data method, or an analysis population definition. These methods cannot be reconstructed from the summary statistics. The recalculations are therefore useful for reading the posted group summaries, but they are not substitutes for a fully specified trial analysis.

11. Confidence Intervals and Precision

Precision concerns how narrowly the data estimate a group difference. The primary risk-difference estimate is -0.02, and its confidence interval extends from -0.112 to 0.072. Because the interval crosses zero, the posted retention results are compatible with no group difference as well as with contrasts in either direction. The estimate alone should not be read as a definitive indication that one condition retained more participants.

The abstinence comparison also has a confidence interval that includes zero. The posted count is five participants meeting the outcome definition in each group, but the interval allows uncertainty around the difference in the underlying proportions. Similar observed counts do not establish equivalence, especially when the interval remains compatible with more than one plausible direction of effect.

For acceptability and satisfaction, the mean difference is 0.39, with a confidence interval from -2.204 to 2.984. The interval contains both negative and positive differences, so the estimate is not precise enough to establish the direction of a population contrast. For self-efficacy change, the reported unadjusted recalculated p-value is <0.001, and the estimated mean difference is -0.34. The registry record does not provide a trial-reported confidence interval for this outcome. The absence of a posted interval makes it harder to judge the precision of the estimated score contrast directly from the registry entry.

In general, confidence intervals are affected by the amount of information, variability, and analysis assumptions. The reported group counts and scores are limited, and the registry record does not explain whether the recalculated intervals account for school clustering. Precision should therefore be judged from the posted intervals together with the missing methodological details, rather than from a point estimate or p-value alone.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size figures are planning illustrations based on the observed effects, not the trial’s original design calculation. For these outcomes, the figures are participants per arm. The planning assumptions listed in the registry material are a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect set to the stated fraction of the observed effect. The time-to-event convention of total events does not apply to these outcomes.

Each planning row asks how many participants per arm would be needed, under those assumptions, to have an 80% or 90% chance of detecting the specified effect if that effect were the true one and the test assumptions held. The 90% power column represents a greater chance of detecting that effect than the 80% column, and consequently requires more participants per arm. These are hypothetical planning quantities, not observed power.

Rows using 100%, 75%, and 50% of the observed effect illustrate how the required sample size changes when the target effect is set smaller than the observed estimate. Smaller effects are harder to distinguish from random variation, so they require more participants. For example, the retention planning figures rise from 1,547 participants per arm at 100% of the observed effect to 5,467 participants per arm at 50% for 80% power. Those figures depend strongly on the observed effect used as the starting point and should not be interpreted as a recommendation or as evidence that the trial was designed with those targets.

The curve should be read as a visual companion to these assumptions: it describes how planning requirements vary with the effect size used, rather than adding evidence about what happened in the completed study. The original trial’s sample-size assumptions and justification are not reported in the registry record.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.969; treatment proportion p₁ = 0.949; average p̄ = 0.959.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.2813 = 0.5513.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.2809 = 0.2364.
4. n = (0.5513 + 0.2364)² / (-0.0200)² = 1,546.5, rounded up to 1,547 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
p0 <- 0.96875                          # control proportion
p1 <- 0.948717948717949                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(5140915)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 1,547 (80% power), 2,070 (90% power)
 75% of observed effect: n per arm = 2,591 (80% power), 3,467 (90% power)
 50% of observed effect: n per arm = 5,467 (80% power), 7,318 (90% power)
power.prop.test: 1546.5 
Simulated power at n = 1,547 per arm: 0.806 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome and eight secondary outcomes. The primary outcome concerns retention, while the secondary outcomes cover acceptability and satisfaction, cotinine-validated abstinence, counts of intervention interactions and content use, and changes in participant scores or stage. Examining multiple outcomes creates a multiplicity issue: the more comparisons made, the greater the opportunity for an apparently striking result to arise by chance. This is a general statistical concern, not proof that any particular posted result is spurious.

The registry record does not report a multiplicity adjustment, a hierarchy of outcomes, or a plan specifying which secondary comparisons were confirmatory. The self-efficacy recalculation has p < 0.001, but without a reported analysis plan and multiplicity strategy, it should be treated as an unadjusted secondary finding. The other unadjusted p-values also should not be read as a coordinated set of confirmatory tests. The registry reports one analysis in its general analysis count, but does not explain how that count relates to the several outcome summaries available.

Missing-data handling is also not reported in the registry record. The primary endpoint counts are presented with group denominators, while the posted secondary analyses use different group counts for some outcomes. The record does not explain why the analysis counts differ, how unavailable measurements were handled, whether participants were analyzed according to their randomized group, or whether any imputation or sensitivity analysis was used. No missing-data mechanism should be inferred from the counts alone.

The analysis population is not defined in the registry record. It does not state whether the analyses followed an intention-to-treat principle, included all randomized participants, or used another population definition. The record also does not describe adjustment for school clustering, despite identifying schools as the units randomized. These gaps matter because population definitions, missing observations, multiplicity, and clustering can all affect uncertainty and interpretation. The posted summaries remain informative descriptions, but their inferential status is limited by these unreported methods.

15. 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 summary reports zero serious adverse events in the intervention group and zero in the control group. It also reports zero other adverse events in both groups and zero deaths in both groups. The registry lists 39 participants at risk for the adverse-event summaries in the intervention group and 32 in control.

These figures mean that no events were recorded in the categories shown in the registry record. They do not establish that the intervention has no risk or that no unrecorded or unreported events occurred. A zero count is an observation within the study’s recorded safety data, not proof that the underlying event probability is zero. The record does not describe the event-collection procedures, definitions, follow-up completeness, or whether events were assessed for relationship to the intervention.

The safety findings should also be understood in the context of the study’s size and follow-up. The primary outcome timeframe is 3 months, and the registry record does not give a separate detailed safety follow-up schedule. With no reported serious-event terms, there is no specific serious event to characterize from this record. These counts are descriptive and do not replace broader safety evidence or establish comparative safety with precision.

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

The posted primary result describes retention in a completed randomized school-based study of a mobile peer-driven intervention compared with cessation materials. The groups had high observed counts for the registered retention endpoint, and the unadjusted recalculated estimate of the difference is close to zero. Its confidence interval is broad enough to include differences in either direction. This is evidence about the recorded endpoint in this study, not a final answer about how the intervention performs in other settings.

The primary endpoint does not directly measure whether participants quit vaping. Cotinine-validated 7-day point-prevalence abstinence was listed separately as a secondary outcome, with five participants in each group meeting the definition. Its estimate is uncertain, and the confidence interval includes no difference. These results do not establish that the groups have the same abstinence rate, nor do they show a clear difference between conditions.

The self-efficacy change comparison shows an unadjusted statistical contrast, but the registry record does not explain the scale’s direction or establish what magnitude would be meaningful. A statistical result does not automatically translate into a meaningful change for adolescents. Likewise, participant satisfaction, engagement with intervention components, and stage of change address distinct concepts and cannot be inferred from retention alone.

The intervention is a package of peer messages, text-based coaching, and gamification, compared with cessation materials. This design does not isolate the contribution of each component. The available registry results also leave important analysis details unreported, including missing-data procedures, analysis populations, multiplicity handling, and accounting for school-level clustering. Conclusions should remain bounded by the posted outcome definitions and these uncertainties.

In general, a randomized comparison can support causal interpretation when its design and analysis are appropriately implemented, but the registry summary alone does not provide enough methodological detail to assess every assumption. The findings are best read as estimates from this completed study, with uncertainty, rather than as proof of benefit, lack of benefit, equivalence, or general effectiveness.

17. Why This Trial Matters Statistically

This study raises statistical questions common to behavioral and digital interventions. A program can be evaluated not only by a clinical outcome such as abstinence, but also by whether participants can be recruited, retained, and engaged with its components. Those outcomes answer different questions and should be kept distinct. The registered primary endpoint is retention, while vaping abstinence and intervention experience are secondary outcomes.

The school-based randomization is especially relevant to analysis. When groups are assigned by school, participants within a school may share characteristics or experiences. In general, this clustering can make participant observations less independent than an analysis treating each person as unrelated. The registry record does not report whether the trial analysis accounted for school-level clustering, so the unadjusted recalculations should not be mistaken for a complete analysis of the randomized design.

The record also illustrates why effect estimates and uncertainty matter more than a single significance label. A point estimate gives a direction and scale, while a confidence interval communicates the range of contrasts compatible with the observed data. Results for retention and abstinence remain uncertain in both directions. The self-efficacy result has a small unadjusted p-value, but interpretation still depends on the scale, multiplicity, and analysis assumptions.

Finally, planning estimates based on observed effects can help readers see how sample-size requirements change under specified assumptions, but they do not explain the original design or prove that the completed trial was adequately powered. Since the original sample-size justification is not reported, the planning illustrations should be understood as hypothetical. Clear reporting of design, analysis populations, missing data, clustering, and multiplicity would make the statistical evidence easier to evaluate.

18. 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 primary endpoint is described as the number who remained active at 3 months, but the registry does not define the activity required for classification. This limits the ability to interpret retention as a specific level of program engagement. The endpoint also does not directly measure vaping cessation, which appears as a separate secondary outcome.

Although the study is described as school-randomized, the registry record does not report the number of schools, the allocation procedure, or whether analyses accounted for clustering within schools. The unadjusted comparisons use posted group summaries and may not reproduce the trial’s intended analysis. The record does not report a full statistical analysis plan, analysis populations, or missing-data procedures, so the reasons for different group counts across outcomes cannot be established.

The available registry results cover only some of the listed secondary outcomes. Results for peer-coaching interactions, peer videos viewed, games engaged in, stage of change, and nicotine-addiction severity are not reported in the registry record. A multiplicity strategy is also not reported, which makes isolated secondary p-values less suitable for confirmatory interpretation.

The intervention contains several components, and the control receives cessation materials. The comparison therefore cannot identify the separate contribution of peer messaging, coaching, or gamification. The registry does not give detailed demographic characteristics, eligibility criteria, the age distribution, or a detailed definition of masking. It also does not report the original sample-size justification. These omissions constrain assessment of representativeness, precision planning, and generalizability beyond the study context.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Vaper to Vaper: A Multimodal Mobile Peer Driven Intervention to Support Adolescents in Quitting Vaping — NCT05140915.
• Registry record last updated 2025-09-04; status last verified 2025-09.
• Results first posted 2025-04-23.
• 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.

22. Record Summary

The registry record describes a completed, randomized, single-masked, parallel-group study with 71 enrolled participants. Schools were assigned to a mobile peer-driven intervention or to e-cigarette cessation materials. The intervention combined tailored peer messages, text-facilitated peer coaching, and gamification.

The primary outcome was participant recruitment and retention at 3 months. Posted counts were 37 of 39 in the intervention group and 31 of 32 in control. The unadjusted recalculated risk difference was -0.02, with a confidence interval spanning zero. Secondary results include acceptability and satisfaction, cotinine-validated abstinence, and self-efficacy change; other listed secondary outcomes do not have results reported in the registry record.

Interpretation is limited by unreported details on the original sample-size rationale, missing data, analysis populations, multiplicity, and school-level clustering. The posted findings describe the registry outcomes but do not, by themselves, establish a definitive effect on vaping cessation or the separate contribution of each intervention component.