Cigarette and E-cigarette Nicotine Content in an Electronic Tobacco Marketplace (ETM): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Cigarette and E-cigarette Nicotine Content in an Electronic Tobacco Marketplace (ETM) (NCT05320887), a randomized na study. The primary outcome is Number of Cigarettes Purchased.

2. Clinical Question

3. Trial Design

This was a randomized, single-masked, factorial study conducted in an Electronic Tobacco Marketplace. The registry lists the phase as not applicable and reports an enrollment of 69. The study status is completed. The recorded start date is 2022-07-27, and primary completion is dated 2023-07-31. Wake Forest University Health Sciences is listed as the sponsor.

The four intervention conditions combine two nicotine-content categories for vapes—normal and low—with two e-liquid flavor categories—all flavors and tobacco e-liquids. The registry’s brief description frames the study as an examination of whether banning normal nicotine content in cigarettes would be sufficient to encourage smokers to switch products, or whether higher-nicotine and/or flavored e-cigarette alternatives would also be needed to change smoking behavior. That statement describes the study’s motivation, not a conclusion from the reported results.

The primary outcome was assessed at Visit 6, approximately 4 weeks after baseline, using cigarette purchases made during Shopping Trip 7. Its population is specifically described as participants who purchased cigarettes during that trip. Results are posted for 29 participants in the normal nicotine content vape with tobacco e-liquids group and 32 in the low nicotine content vape with tobacco e-liquids group. The two all-flavor groups have no estimable primary-endpoint values in the record.

Details about how randomization was generated, whether allocation was concealed, who was masked, and whether the analysis followed the assigned groups are not reported in the registry record. The record also does not explain how the factorial effects or interactions were modeled.

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: Out of the initial 69 participants enrolled, 5 people were lost to follow up or withdrew between screening eligible and getting randomized to a group leaving 64 participants randomized. Staff instructed participants that one iteration of the task would be randomly selected and would determine which products (flavor e-liquids or tobacco e-liquids) they would use during the assessment. In reality, participants were only randomly assigned to tobacco e-liquid and never assigned to flavor e-liquid.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Among those participants who purchased cigarettes in Shopping Trip 7 at Virtual Visit 6, the average number of cigarettes purchased (in an experimental tobacco marketplace where packs of very low nicotine content (VLNC) cigarettes, bottles of e-liquid matched to their randomization condition, boxes of nicotine gum were available).

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: Participants that completed all virtual shopping trips before randomization of take-home products. Participants were told they may have a chance of taking home "all flavor e-liquids" to prevent purchasing bias, but they were only able to take home tobacco e-liquids.

6. Primary Endpoint

The registry lists the primary outcome as Number of Cigarettes Purchased, measured over Visit 6 approximately 4 weeks after baseline.

The primary endpoint is the average number of cigarettes purchased by participants who bought cigarettes during Shopping Trip 7 at Virtual Visit 6, approximately 4 weeks after baseline. It is a continuous measure: each participant’s purchase quantity contributes to a group average. The record describes the measure as analyzed both as raw data and using derived behavioral-economic measures, but the posted primary outcome is the average number of cigarettes purchased.

Purchasing is a behavioral measure of product choice in the study’s experimental marketplace. It captures what participants selected in that setting, rather than directly measuring all cigarette use outside the marketplace. The endpoint therefore addresses a particular aspect of smoking behavior under the study conditions; it should not be treated as a measure of every participant’s total tobacco consumption.

The record reports a mean and standard deviation for the two tobacco-e-liquid groups with estimable results. It does not report a mean for either all-flavor group, and it does not provide a between-group effect estimate or uncertainty interval. The reason that endpoint values are unavailable for those groups is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a continuous variable summarized by a mean and standard deviation. In general, a mean describes the central average of observed measurements, while the standard deviation describes how dispersed individual measurements are around that average. Neither statistic, by itself, expresses the uncertainty in the estimated group mean or the uncertainty in a difference between groups. A confidence interval or a model-based comparison can provide information about that uncertainty, but neither is reported for this primary endpoint.

What the reported summaries can show

The posted means describe the average cigarette-purchase quantities for the two groups with estimable results. The corresponding standard deviations show that individual purchase quantities varied within each group. The standard deviation is not a confidence interval and should not be read as the range containing all participant values. The registry does not report individual observations, distributional summaries beyond the mean and standard deviation, or confidence intervals for these means.

For a continuous endpoint, a comparison between groups would ordinarily estimate a difference in averages or use a model suited to the endpoint and study design. The registry does not post such an estimate, its uncertainty, or a hypothesis test. It is therefore not possible to use the primary results to assess the statistical evidence for a difference between the two reported groups. No recalculated comparison is available in the record.

Why variability and endpoint definition matter

Purchase counts can vary substantially across individuals. When data are highly variable, a group average may be sensitive to participants with unusually large purchases, and the standard deviation alone does not reveal the distribution’s shape. General statistical practice may use descriptive plots or methods appropriate to the outcome’s distribution to investigate such features. The registry does not report a distributional assessment or details of the statistical model used for the stated raw-data and derived behavioral-economic analyses.

The endpoint is also conditioned on a purchase: it includes participants who bought cigarettes during Shopping Trip 7. This defines a narrower analysis population than all randomized participants. In general, conditioning an outcome analysis on a post-randomization behavior can affect how groups are interpreted, because membership in the analyzed population may differ from assignment to the original groups. The record does not describe how many participants were randomized to each arm, how many did not meet the purchase condition, or how this restriction was handled analytically. The posted endpoint counts should not be treated as a full intention-to-treat analysis.

Factorial structure and incomplete estimates

A factorial design organizes interventions around multiple factors. Here, the listed conditions combine nicotine content and flavor availability. In general, an analysis of a factorial design can estimate effects associated with each factor and can assess whether the effect of one factor differs across levels of another. Such an interpretation depends on the analysis model and on having outcome information adequate for the relevant conditions. The registry labels this trial factorial but does not report the model, factor-effect estimates, interaction analysis, or a statistical analysis plan. Because the primary-endpoint values are unavailable for both all-flavor groups, the posted results do not furnish a complete set of group summaries for the four conditions.

Randomization can support comparisons of assigned conditions when outcomes are analyzed in a way consistent with the design, but the registry’s label alone does not specify the implementation or analysis. Details about sequence generation, allocation concealment, masking procedures, covariate adjustment, and treatment of protocol deviations are not reported in the registry record. The record also does not state whether an interim analysis was planned or conducted.

Planning and precision

Sample-size planning and analysis of observed outcomes answer different questions. General planning illustrations can describe how many participants per arm might be needed under stated assumptions to detect a specified effect with a chosen error rate and power. They do not establish the power achieved by the completed trial, and they do not repair missing outcome estimates. The registry record does not report the trial’s own sample-size justification or enough primary-outcome inferential results to assess the precision of a treatment comparison. Any planning illustration based on an observed effect should be read as a planning exercise, not as observed power.

In sum, the available primary-outcome statistics are descriptive summaries for two groups. The inferential methods, model assumptions, handling of missing values, and analysis populations beyond the endpoint’s purchase-based definition are not reported in the registry record. Those omissions limit both reproducibility and the strength of conclusions that can be drawn from the posted results.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Normal Nicotine Content Vape With Tobacco E-liquid", "Low Nicotine Content Vape With Tobacco E-liquids")
n   <- c(29, 32)
m   <- c(154.7, 119.2)
sp  <- c(131.7, 55.5)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Normal Nicotine Content Vape With Tobacco E-liquid  29  154.700  131.700  104.604  204.796
CARM  Low Nicotine Content Vape With Tobacco E-liquids  32  119.200  55.500  99.190  139.210

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 8 secondary outcomes, including e-liquid milliliters purchased, completion of flavor and nicotine-content choice projections, perceived risk scores, product evaluation scores, withdrawal scores, smoking-urge scores, tobacco-product interest scores, and tobacco-policy questionnaire scores. It reports 13 outcome measures overall. No analyses are posted. The record does not report which outcomes were tested, whether any were designated as key secondary outcomes, or whether multiplicity was addressed through a prespecified testing sequence or another method.

Multiplicity matters when many outcomes or comparisons are examined: the chance of at least one apparently notable result can increase if each is interpreted without accounting for the broader set of tests. This is a general statistical concern, not evidence that a particular adjustment was or was not performed. Since no inferential analyses are reported, the registry does not allow readers to evaluate multiplicity-adjusted or unadjusted statistical findings for the listed outcomes.

The primary outcome population is restricted to participants who purchased cigarettes in the specified shopping trip. The record does not report the number of randomized participants in each arm, the number excluded by this purchase condition, or reasons for unavailable endpoint values. It also does not state how missing outcomes were handled, whether imputation was used, or whether sensitivity analyses were performed. The absence of endpoint estimates for the two all-flavor groups cannot be attributed to a particular missing-data mechanism based on the registry information.

The analysis population beyond the endpoint’s stated definition is not reported in the registry record. Whether the primary analysis was intention-to-treat, per-protocol, or another approach is not specified. These gaps mean the reported group summaries cannot be assumed to represent all randomized participants.

12. 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 non-serious adverse event terms

The registry reports no serious adverse events among the 29 participants at risk in the normal nicotine content vape with tobacco e-liquids group, and none among the 32 participants at risk in the low nicotine content vape with tobacco e-liquids group. It reports 0 deaths in both groups. Other adverse events affected 1 participant in the normal nicotine content group and 2 participants in the low nicotine content group.

For the two all-flavor groups, the registry reports no participants at risk. Those entries should not be interpreted as evidence that no adverse events occurred among participants in those conditions; a zero at-risk count does not provide an evaluable safety denominator. The reason those groups have no reported at-risk participants is not stated in the registry record.

These figures are descriptive registry counts. The record does not provide event details, severity or relatedness information for the other adverse events, exposure time, or a statistical comparison between groups. The posted counts therefore support only a narrow reading of what was reported, not a comprehensive comparison of safety across all four conditions.

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

The primary-endpoint results show average cigarette purchases in a virtual marketplace for two of the four listed intervention conditions. The reported mean was 154.7 cigarettes in the normal nicotine content vape with tobacco e-liquids group and 119.2 in the low nicotine content vape with tobacco e-liquids group. Their standard deviations were 131.7 and 55.5, respectively. The endpoint was measured among participants who purchased cigarettes in Shopping Trip 7 at Virtual Visit 6, approximately 4 weeks after baseline.

These descriptive values do not establish that one condition caused a different purchase pattern from another. The registry does not report an inferential comparison, confidence interval, or p-value. The two all-flavor conditions lack estimable endpoint values, so the posted primary results do not answer the full set of comparisons implied by the factorial design. The registry’s stated rationale about nicotine content, flavor availability, and smoking behavior is a study objective, not a finding demonstrated by these posted statistics.

The measure concerns purchasing in the experimental marketplace. It does not, on its own, establish how many cigarettes participants smoked in daily life, whether purchasing translated into consumption, or whether behavior persisted beyond the recorded visit. Nor does it establish effects on health outcomes. The record does not report results for the listed secondary outcomes, so no conclusions about those measures are supported by the posted analysis information.

The appropriate interpretation is therefore limited: two group averages and their variability are reported for a selected endpoint population, while the comparative analysis and estimates for the remaining conditions are unavailable. The values are useful descriptive information, but they do not settle the trial’s broader research question.

14. Why This Trial Matters Statistically

This study illustrates why a randomized label and a stated factorial design do not by themselves guarantee that all intended comparisons can be interpreted from a registry record. The design lists combinations of nicotine content and flavor availability, but the primary endpoint has estimable values for only the two tobacco-e-liquid groups. Without results for the all-flavor groups, the posted data cannot show the full pattern across the four conditions or support a complete assessment of the two design factors.

It also illustrates the distinction between descriptive statistics and inferential evidence. Means and standard deviations give readers a useful account of the observed endpoint values and their spread. They do not quantify uncertainty about a group difference. An effect estimate with an uncertainty interval and a clearly described analysis would be needed to assess how precisely the comparison is estimated. None is reported for this primary endpoint.

The purchase-based endpoint population is another statistical issue. The primary result is defined among people who made a purchase, rather than explicitly among everyone assigned to a condition. That distinction matters because the population used in an analysis affects the question answered. Reporting how many randomized participants met the endpoint definition, how unavailable values were handled, and how the analysis relates to random assignment would make the results easier to evaluate.

Finally, the record lists multiple secondary outcomes but posts no analyses. This makes it impossible to assess the reported evidence across outcomes or to understand how multiplicity was managed. These are reporting and interpretation concerns; they do not prove that a particular analysis was inappropriate. They show why transparent endpoint definitions, complete arm-level results, and prespecified statistical methods are important for evaluating a clinical trial.

15. 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 most direct limitation of the posted primary results is incomplete arm-level outcome reporting. The two all-flavor groups have no estimable values, and the registry does not explain why. The reported means therefore cover only two of the four intervention conditions and do not permit a complete descriptive comparison of the factorial combinations.

The primary endpoint applies only to participants who purchased cigarettes during a specified shopping trip. The record does not report the number of participants assigned to each condition, the number who did not make a qualifying purchase, or how that selection affected the analysis. Although overall enrollment is reported as 69, the endpoint summaries are based on 29 and 32 participants in the two groups with results. The reason for the difference between the overall enrollment and these endpoint counts is not reported in the registry record.

No inferential results are posted for the primary endpoint. There are no reported confidence intervals, tests, adjusted estimates, or model specifications. The registry also does not report the trial’s sample-size justification, missing-data methods, randomization details, masking procedures, or planned analysis of the factorial effects. These omissions limit assessment of precision, reproducibility, and risk of bias.

The endpoint is a marketplace purchase measure at a specified visit, not a direct record of all tobacco consumption or a long-term health outcome. The record does not establish how closely marketplace purchasing corresponds to behavior outside that setting. The limited safety information is also incomplete for the two groups with no participants reported at risk. These constraints should inform interpretation without implying that unreported details were necessarily absent from the study itself.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Cigarette and E-cigarette Nicotine Content in an Electronic Tobacco Marketplace (ETM) — NCT05320887.
• Registry record last updated 2024-10-09; status last verified 2023-03.
• Results first posted 2024-10-09.
• 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.

19. Record Summary

The registry record describes NCT05320887, “Cigarette and E-cigarette Nicotine Content in an Electronic Tobacco Marketplace (ETM),” as a completed randomized, single-masked factorial study sponsored by Wake Forest University Health Sciences. It reports enrollment of 69 and lists four vape conditions combining normal or low nicotine content with all-flavor or tobacco e-liquids.

The primary endpoint is the average number of cigarettes purchased during Shopping Trip 7 at Virtual Visit 6, approximately 4 weeks after baseline, among participants who purchased cigarettes. Results are reported for the normal nicotine content vape with tobacco e-liquids group and the low nicotine content vape with tobacco e-liquids group. The all-flavor groups have no estimable values. No inferential analyses are posted, and the registry does not report the reason for unavailable values, the missing-data approach, or the statistical analysis plan.