Perceptions of Cigarette Smoking in Young Adults: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Perceptions of Cigarette Smoking in Young Adults (NCT03953508), a randomized na study. The primary outcome is Subjective Response to Smoking Cigarettes From the Cigarette Evaluation Scale.

2. Clinical Question

3. Trial Design

The registry identifies NCT03953508 as “Perceptions of Cigarette Smoking in Young Adults,” with the official title “Menthol and Non-Menthol Cigarette Smoking in Young Adults.” The sponsor is the University of Oklahoma. The study is marked completed, randomized, unmasked, and crossover; its phase is listed as not applicable. The recorded enrollment is 199. The study start is 2020-08-01, and primary completion is 2022-12-31.

The study focuses on young adults who smoke menthol or non-menthol cigarettes. The arm descriptions characterize participants according to the cigarette type they prefer. Although the design is labeled crossover, the registry record does not report the sequence of cigarette exposures, the number or timing of crossover periods, or how the crossover designation relates to the comparison of preferred-cigarette groups at baseline. Those procedural details should not be inferred from the design label alone.

The primary outcome population is participants ages 18-26 who completed the baseline or first study visit. The posted primary summaries include 60 participants in the menthol group and 61 in the non-menthol group. The brief summary describes menthol and non-menthol groups of n = 125 each, while recorded enrollment is 199. The registry record does not explain how those figures relate to one another or whether the brief-summary counts refer to a target, a different analysis population, or another stage of the study.

Outcomes span a baseline subjective-response rating and later measures, including a behavioral choice task, past 30-day tobacco product use, and cigarettes per day. The registry also lists intentions to smoke menthol cigarettes and average daily craving among secondary outcomes. Detailed numerical summaries for those latter outcomes are not included in the posted results described in the record.

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: The order in which phases occurred differed as a result of COVID-19 restrictions on in-person data collection. Some participants started EMA first and then began laboratory data collection when in-person data collection was allowed. Other participants started laboratory data collection first (when COVID restrictions were lifted), and then did EMA after laboratory data collection. Thus, the participant flow may appear unbalanced.

Baseline

Reasons for not completing this period:

Ecological Momentary Assessment

Laboratory Period

6-month Follow-up

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Young adult menthol and non-menthol smokers, ages 18-26 who completed the baseline/first study visit

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: Number of participants who completed the baseline survey and attended the first study session to smoke their usual brand cigarette. Some participants completed the baseline survey remotely, due to COVID, and then came to the laboratory to complete the first study visit. Not everyone who completed the baseline survey remotely showed up for the first study visit.

6. Primary Endpoint

The registry lists the primary outcome as Subjective Response to Smoking Cigarettes From the Cigarette Evaluation Scale, measured over immediately after smoking usual brand cigarette, at baseline.

The primary endpoint is the mean score on the Cigarette Evaluation Scale for subjective response to smoking a participant’s usual-brand cigarette. The rating was recorded immediately after smoking at baseline. The registry describes the score as a measure of subjective satisfaction: 1 means not at all and 7 means extremely. Higher scores indicate a greater positive subjective response. The stated minimum is 1 and the maximum is 7.

A subjective-response measure captures participants’ reported experience rather than a directly observed smoking behavior or a clinical event. It is used to characterize how participants rate the cigarette experience. Comparing group means offers a compact description of average ratings, but it does not show how responses are distributed among individuals, whether participants’ experiences were alike, or what caused any group difference.

The primary summaries are means with standard errors for the menthol and non-menthol groups. The registry’s reported analysis is an ANCOVA, but its adjusted estimate and confidence interval are not reported in the registry record. The posted group means are 4.68 for menthol and 4.5 for non-menthol. The recalculated unadjusted mean difference is -0.18, with a 95% confidence interval that includes zero. These summaries describe the recorded baseline ratings among participants in the primary outcome population; they should not be read as evidence of a causal effect of flavor type.

7. Results Posted in the Registry

• Non-menthol: mean 4.50 versus 4.68 on control; difference -0.18 (95% CI -0.62 to 0.26), standardized effect d = -0.14; z-test p = 0.426.

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.

Number of Clicks for Menthol Cigarette Puffs on the Behavioral Choice Task

• 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:
  • Non-menthol Status: mean 104.11 versus 1,245 on control; difference -1,140 (95% CI -1,266 to -1,015), standardized effect d = -3.45; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Non-menthol Status than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Quantity of Past 30-day Tobacco Product Use

• 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:
  • Non-menthol Status: mean 2.00 versus 1.30 on control; difference 0.70 (95% CI 0.19 to 1.21), standardized effect d = 0.74; z-test p = 0.007.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Non-menthol Status than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Cigarettes Per Day

• 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:
  • Non-menthol Status: mean 9.50 versus 9.90 on control; difference -0.40 (95% CI -3.08 to 2.28), standardized effect d = -0.05; z-test p = 0.769.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Non-menthol Status and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes cover different aspects of cigarette choice and tobacco use, and their results do not all point to the same degree of group separation. The registry’s listed outcomes include behavioral choice, past 30-day tobacco product use, intentions to smoke menthol cigarettes, cigarettes per day, and average daily craving. Numerical results are posted for the choice task, past 30-day product use, and cigarettes per day; numerical summaries for intentions and craving are not reported in the registry record.

This mix does not simply replicate the primary subjective-response measure. The primary endpoint is a baseline rating after usual-brand smoking, whereas the secondary outcomes include a later choice task, a follow-up report of product use, and daily smoking quantity. Measures taken at different times and addressing different behaviors can diverge without contradiction. Their results should be interpreted as specific to each outcome and analysis population, rather than combined into a general claim about cigarette flavor or participant behavior.

The secondary p-values are unadjusted in the recalculations, and the registry does not report a multiplicity correction. When many outcomes are analyzed, some may appear statistically notable by chance alone. This makes isolated secondary findings less persuasive than a prespecified primary result supported by a clearly reported analysis plan. The registry lists ten outcome measures and ten analyses, but the plan for controlling the overall chance of false-positive findings is not reported in the registry record.

Counts differ across the posted secondary summaries, and some follow-up summaries include fewer participants than the primary analysis. Without information on missing data and analysis populations, it is difficult to know whether contrasts across endpoints reflect outcome differences, differences in who contributed data, or both. The secondary findings can add context, but they do not replace the primary result or resolve its uncertainty.

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

• Number of Clicks for Menthol Cigarette Puffs on the Behavioral Choice Task
• Quantity of Past 30-day Tobacco Product Use
• Number of Participants With Intentions to Smoke Menthol Cigarettes
• Cigarettes Per Day
• Average Daily Craving From Smoking

9. Statistical Interpretation

10. Statistical Methods Explained

The registry records a randomized, unmasked crossover design and lists ANCOVA as the primary reported method. The numerical recalculation uses the posted group means and standard errors to form a simple unadjusted comparison. These are different analyses: the sponsor-reported ANCOVA is the trial’s own analysis, while the recalculation does not incorporate adjustment variables or the study’s full participant-level data. The adjusted estimate, confidence interval, covariates, and further details of the ANCOVA are not reported in the registry record.

What does a mean difference describe?

A mean is an average of the recorded scores in a group. A mean difference expresses how far apart two group averages are, with the direction depending on which group is subtracted from which. The recalculated primary difference is -0.18 for the non-menthol group relative to the menthol group. This is a descriptive contrast in the posted baseline summaries. It does not, by itself, account for other participant characteristics, explain why the groups may differ, or demonstrate a causal effect.

The primary endpoint is a bounded rating scale, with values from 1 to 7. The reported group means summarize the average rating, but a mean does not display the full distribution of scores. The standard errors describe uncertainty around estimated group means, not the spread of individual ratings. The posted standard error is 0.16 in each group. A standard deviation, which describes variation among individual scores, is not reported for this primary outcome.

What does a confidence interval convey?

A confidence interval expresses the uncertainty around an estimated contrast under the assumptions of the analysis used to calculate it. A wider interval indicates less precision than a narrower interval. For the primary unadjusted contrast, the interval includes zero. That means the posted summary statistics are compatible with no group difference as well as with differences in either direction within the interval. It does not establish that the groups are identical, nor does it establish that a difference is present.

A p-value describes how compatible the observed data are with a specified null hypothesis under a statistical model. The unadjusted primary p-value is 0.426. The sponsor reports p >.05 for the ANCOVA. A p-value is not the probability that the null hypothesis is true, and it does not convey the size or practical importance of an estimated difference. The estimate and its interval are needed to describe magnitude and precision.

Why distinguish adjusted and unadjusted analyses?

An adjusted analysis can account for specified covariates, whereas the simple recalculation compares the posted group summaries without such adjustment. Adjustment can change an estimate or its uncertainty, depending on the model and the data. The registry identifies ANCOVA as the reported primary method but does not identify the adjustment variables or post an adjusted estimate or interval. Consequently, the recalculated difference and p-value should not be substituted for the sponsor’s analysis. There is no reported discrepancy between the posted result and the recalculation, but the sponsor’s own analysis remains the relevant reported analysis.

The crossover designation also matters for statistical interpretation. In a crossover study, observations may be related within the same participant when participants contribute data under more than one exposure. Accounting for that relation can be important because treating related observations as independent may misrepresent uncertainty. However, the registry record does not describe the exposure sequence, which outcomes were measured in each period, or whether the reported methods accounted for within-participant dependence. The simple summary-statistic recalculation should therefore be understood as unadjusted rather than as a complete analysis of a crossover dataset.

How should the secondary methods be read?

The posted secondary analyses use different methods: ANOVA for the behavioral choice task and two-sided t-tests for past 30-day tobacco product use and cigarettes per day. Those method labels indicate broad analysis types, but the record does not report additional modeling details, covariate adjustments, diagnostics, or confidence intervals from the sponsor analyses. The recalculated comparisons are simple unadjusted contrasts of posted means. They do not reproduce any adjustments or other features that might have been used in the original analyses.

For continuous outcomes, the posted means are accompanied by standard deviations for the secondary measures. Standard deviation describes participant-to-participant variation; it is not the standard error of a group mean. The participant counts and variability differ by outcome, so the precision of estimates can differ as well. In general, greater variability or fewer observations tends to make an estimate less precise. This is a general statistical relationship, not a claim about the study’s unreported analysis procedures.

The number of outcomes and analyses matters because examining multiple endpoints creates multiple opportunities for apparently notable results. Unless a statistical plan specifies how multiplicity is handled, individual unadjusted p-values do not account for the whole set of comparisons. The registry lists ten outcome measures and ten analyses, but a multiplicity procedure is not reported in the registry record. As a result, secondary p-values should be interpreted as outcome-specific and exploratory rather than as a single confirmatory conclusion.

11. Confidence Intervals and Precision

The primary group means are 4.68 for menthol and 4.5 for non-menthol, with a standard error of 0.16 in each group. The unadjusted mean difference is -0.18. Its 95% confidence interval includes zero, so the posted data do not pin down the direction of the underlying group contrast. The interval also signals that the estimate should not be read as an exact measure of the difference.

Precision is distinct from statistical significance. A result can have an estimate near zero while still allowing a range of potentially relevant differences, and a result with a small p-value does not automatically imply a precise or important effect. The primary interval is the most direct way to assess uncertainty in the recalculated contrast. The registry does not report a confidence interval for the adjusted ANCOVA result, so the precision of the sponsor’s primary estimate cannot be assessed from its posted analysis summary.

Precision varies across the secondary outcomes because their sample sizes and observed variability differ. The choice-task and past 30-day use comparisons have posted confidence intervals, while the registry’s own analyses do not include interval estimates. The cigarettes-per-day recalculated interval extends from -3.075 to 2.275, spanning zero and allowing values in either direction. This makes clear that the estimate is not sharply determined by the posted summary data.

These intervals quantify sampling uncertainty under their calculation assumptions; they do not incorporate uncertainty about missing observations, unreported adjustments, or the unreported details of the crossover analysis. They also do not resolve whether differences are practically important. The registry record does not state a threshold for a meaningful change on the subjective-response scale.

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 planning figures are participants per arm, not total events. They are planning illustrations based on the observed effect, not the trial’s original design assumptions. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the effect to detect is the stated fraction of the observed effect. The original sample-size justification and design assumptions are not reported in the registry record.

The 80% power column gives the illustrative number of participants per arm for a design with an 80% chance of detecting the specified effect if that effect is real and the planning assumptions hold. The 90% power column gives the corresponding number per arm for a design with a 90% chance under those assumptions. These are hypothetical design calculations. They are not observed power, and they do not describe the probability that the completed study’s result is correct.

The rows illustrate planning for 100%, 75%, and 50% of the observed effect. When the target effect is smaller, it is harder to distinguish from random variation, so more participants are needed under the same planning assumptions. The calculated figures can vary greatly by outcome because the observed effects and variability differ. In particular, calculations based on an unusually large observed effect can yield very small planning figures; those should not be read as a recommended sample size or as evidence that a completed study was adequately powered.

These figures do not account for unreported design features, possible participant loss, or adjustment procedures. They are best read as sensitivity illustrations: they show how the assumed effect size and chosen power level relate to a hypothetical per-arm sample size, rather than documenting the trial’s actual planning process.

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, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -0.180; pooled standard deviation σ = 1.245.
2. n = 2 × (1.96 + 0.842)² × 1.245² / -0.180² = 750.4, rounded up to 751 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
delta <- -0.18                      # observed difference in means
sigma <- 1.24455114922016                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^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 (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(3953508)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 751 (80% power), 1,005 (90% power)
 75% of observed effect: n per arm = 1,335 (80% power), 1,787 (90% power)
 50% of observed effect: n per arm = 3,002 (80% power), 4,019 (90% power)
power.t.test: 751.4 
Simulated power at n = 751 per arm: 0.801 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-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. Analyses Reported by the Sponsor

The registry reports ANCOVA for the primary comparison, with p >.05. It does not post the adjusted estimate, confidence interval, covariates, or further details of that model. The recalculation from the posted group means and standard errors is an unadjusted mean difference of -0.18, with an unadjusted p-value of 0.426 and a confidence interval that includes zero. These results are directionally consistent in the limited sense that neither reports a statistically clear primary group difference.

The sponsor’s analysis takes precedence as the trial’s own reported analysis. The recalculation is not a replacement for ANCOVA: it does not use participant-level data, cannot reproduce adjustment, and may not reflect how the crossover design was handled. The registry records no discrepancy between the sponsor result and the recalculation. Because the sponsor’s numerical estimate and interval are absent, the size and precision of its adjusted contrast cannot be compared directly with the unadjusted calculation.

The same distinction applies to secondary outcomes. The registry identifies ANOVA or two-sided t-tests for the reported analyses, but does not provide their estimates and intervals. Recalculated comparisons from posted summaries are useful descriptive checks, not a substitute for the sponsor’s models or a reanalysis of the complete trial data.

15. Multiplicity, Missing Data and Analysis Populations

The registry lists ten outcome measures and ten analyses. It does not report a multiplicity strategy, such as a hierarchy of outcomes or an adjustment to account for testing multiple hypotheses. Without such information, each secondary p-value should be read as an individual unadjusted result. The more comparisons examined, the greater the chance that at least one result will appear notable by chance. The record does not establish whether a multiplicity plan was specified elsewhere or used in the analysis.

Missing-data methods and the handling of incomplete follow-up are not reported in the registry record. The number of participants contributing to the primary outcome is 60 in the menthol group and 61 in the non-menthol group. Secondary counts vary by outcome; for example, the past 30-day product-use summaries include 24 and 31 participants, while cigarettes-per-day summaries include 62 in each group. The reasons for these differences, the amount and pattern of missingness, and whether any imputation or sensitivity analysis was used are not reported in the registry record.

The analysis populations are also not fully described. The primary population is specified as participants who completed the baseline or first visit, but the registry does not explain whether other analyses included all randomized participants, only participants with observed outcomes, or a different defined population. The recorded enrollment of 199 and the brief-summary counts of n = 125 per group do not align transparently with the posted primary analysis counts; their relationship is not reported in the registry record.

These omissions matter because complete-case summaries can represent a selected subset if participants with missing measurements differ from those observed. That is a general statistical concern, not evidence that such selection occurred in this study. Without the missing-data and analysis-population details, the robustness and comparability of the outcome-specific estimates cannot be fully evaluated.

16. 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 1% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports no serious adverse events in either group and no deaths. For other adverse events, it reports 0 among 60 participants in the menthol group and 1 among 61 participants in the non-menthol group. No serious adverse-event terms are listed.

These counts describe events recorded in the registry and the participant counts at risk for the reported categories. They do not establish that an event was caused by a study exposure, and the record does not provide further details about the single other adverse event. With few events recorded, the figures offer limited information about uncommon harms. The registry record does not report additional event descriptions or a comparative statistical analysis of adverse events.

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

The primary result describes average baseline subjective-response scores among young adult menthol and non-menthol smokers who completed the first study visit. The group means were 4.68 and 4.5, and the unadjusted mean difference was -0.18. The confidence interval includes zero, and the registry reports p >.05 for its ANCOVA. The posted evidence therefore does not show a statistically clear difference on this primary measure, but it also does not prove that the groups are identical.

The endpoint is a self-reported rating on a bounded scale. It reflects participants’ reported subjective response after smoking their usual-brand cigarette, not a clinical outcome or a direct measure of long-term behavior. The result should be kept within that scope. It does not establish whether menthol or non-menthol cigarettes cause a particular experience, nor does it establish the effect of changing cigarette type.

Secondary findings address separate outcomes and time points. They offer additional descriptions of choice-task behavior and tobacco use, but they do not convert the primary result into a causal conclusion. The registry does not report numerical results for every listed secondary outcome, and it does not report a multiplicity strategy or complete details about missing data and analysis populations. Those limitations make broad synthesis of the secondary results uncertain.

The crossover label and randomization entry are part of the recorded design, but the registry does not report enough procedural and analytical detail to establish how the exposure sequence was implemented or how the design was reflected in each analysis. The group descriptions are based on cigarette preference. Without further information, the group comparisons should not be interpreted as a clean estimate of the causal effect of flavor type.

In short, the posted primary data provide an uncertain comparison of average baseline ratings. The secondary results vary by outcome. The registry findings describe what was recorded and analyzed; they do not determine clinical importance, explain why any group contrast occurred, or support medical advice.

18. Why This Trial Matters Statistically

This trial illustrates why a statistical result needs to be read in relation to the outcome, analysis population, and design. The primary endpoint is a subjective rating, and the posted comparison is a modest unadjusted difference with an interval that includes zero. The sponsor’s ANCOVA is reported only through a p-value threshold, leaving the adjusted estimate and its precision unavailable. A p-value alone cannot convey how large or precise the adjusted difference was.

The record also illustrates the distinction between a declared design and the details needed to evaluate its analysis. It is labeled randomized and crossover, while group descriptions classify participants by preferred cigarette type. The registry does not explain the relationship between preference, allocation, and crossover exposure. This makes it important not to treat a design label as a substitute for methods information.

Secondary endpoints can broaden the picture but also create interpretive challenges. Different outcomes have different participant counts and time frames, and the record lists multiple analyses without reporting a multiplicity approach. A statistically notable secondary result deserves more caution when the analysis plan and missing-data handling are not clear.

Finally, planning illustrations based on observed effects are not a record of the original sample-size justification. They show how hypothetical sample size changes with assumed effect size and power, but cannot establish what the investigators planned or whether the completed study had adequate power for its primary question. These distinctions help keep numerical summaries informative without overstating what the registry can establish.

19. 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’s primary analysis reporting is limited: ANCOVA is named and p >.05 is reported, but the adjusted estimate, confidence interval, covariates, and further model details are absent. The unadjusted recalculation cannot fill those gaps or reproduce an analysis based on participant-level data.

There is limited detail about how the randomized crossover design was implemented. The registry does not describe exposure sequence, periods, or how repeated measurements and potential within-participant correlation were handled. At the same time, the group descriptions refer to participants’ preferred cigarette type. The relationship between those descriptions and randomization is not explained.

The record also leaves the analysis populations unclear. The primary summaries include 60 and 61 participants, while counts differ across secondary outcomes. The brief summary gives n = 125 for each preference group, and the recorded enrollment is 199; the relationship between these figures and the outcome-specific counts is not reported in the registry record. Reasons for missing or unavailable observations, and any methods used to address them, are also not reported.

Other limitations include the absence of a reported multiplicity strategy despite multiple outcomes and analyses, incomplete numerical reporting for some listed secondary outcomes, and a lack of sponsor-reported confidence intervals for the posted analyses. The record does not state a threshold for a meaningful difference on the subjective-response scale. These limitations constrain assessment of precision, robustness, and practical importance without implying that a particular bias or problem occurred.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Perceptions of Cigarette Smoking in Young Adults — NCT03953508.
• Registry record last updated 2024-12-16; status last verified 2024-10.
• Results first posted 2024-12-16.
• 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.

23. Record Summary

NCT03953508 is a completed, randomized, unmasked crossover study sponsored by the University of Oklahoma. It concerns menthol and non-menthol cigarette smoking in young adults. The primary outcome is the Cigarette Evaluation Scale subjective-response score immediately after usual-brand smoking at baseline.

The primary group means were 4.68 for menthol and 4.5 for non-menthol. The registry reports ANCOVA with p >.05; the unadjusted recalculation gives a mean difference of -0.18 and a p-value of 0.426, with a confidence interval that includes zero. The registry also posts selected secondary results, but outcome counts vary and analysis details are incomplete. Multiplicity handling, missing-data methods, and further details of the crossover procedures are not reported in the registry record.