Personalized Feedback for Distress Intolerant Smokers: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Personalized Feedback for Distress Intolerant Smokers (NCT03918031), a randomized na study. The primary outcome is Rulers for Smoking Cessation.

2. Clinical Question

In practical terms, the registered comparison asks whether adding feedback about distress tolerance and coping to smoking-focused feedback is associated with different ratings on three smoking-cessation rulers. Those ratings cover how important stopping smoking is to a participant, confidence in quitting within the next month, and readiness to quit within the next month. Higher scores are described as better outcomes for each ruler.

The question is about these self-reported measures, not a reported measure of smoking abstinence. Although the registry lists six outcome measures, it identifies the Rulers for Smoking Cessation as the primary outcome. The other outcome measures and their results are not reported in the registry record. Without posted estimates for the primary measures, the relative pattern of change between groups cannot be assessed from the registry record.

3. Trial Design

The registry describes a randomized, single-masked, parallel-group behavioral trial. Participants were assigned to one of two intervention arms: a personalized feedback intervention addressing smoking and distress tolerance, or a personalized feedback intervention addressing smoking only. The registry record does not describe the randomization sequence, how allocation was concealed, or who was masked.

The record lists enrollment as 121. The study began on 2019-07-15, had a primary completion date of 2021-10-24, and is listed as completed. The sponsor is the University of Houston. The phase is listed as NA. These administrative details do not establish how many participants contributed data to each outcome analysis; the record notes that the overall number differs from the analyzed number because some participants did not complete selected follow-up assessments.

Both interventions are described as brief and computer-delivered, with one session. The distinction between arms is the distress-tolerance component: it is included in one intervention and absent from the smoking-only comparator. Further details about intervention delivery, participant contact, adherence, or fidelity are not reported in the registry record.

The primary outcome was scheduled at baseline, 2-week, and 1-month follow-up. The registry lists six outcome measures, but the record reports zero analyses. It therefore does not give numerical primary-outcome results, group-specific changes, uncertainty intervals, or a statistical comparison between arms. The study design identifies what was intended to be compared; without reported analyses, it does not establish the size or precision of any observed difference.

The record does not report a sample-size justification, a planned statistical model, an analysis population definition, or interim analyses. The registry’s status and dates describe trial administration, not the strength of evidence for an intervention effect. Any conclusion about differences in the primary outcome would require results that are not reported in the registry 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.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Overall number is different from analyzed number due to participants not completing select follow-up assessments.

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 Rulers for Smoking Cessation, measured over Baseline, 2-week, and 1-month follow-up.

The registered primary endpoint is the Rulers for Smoking Cessation, measured in units on a scale and summarized as a mean with a standard deviation. It consists of three separate ratings rather than a single combined score. Motivation asks how important stopping smoking is, with response anchors from 0, “Not important at all,” to 10, “Most important goal of my life.” Confidence asks how confident participants are that they will quit smoking within the next month, from 0, “Not at all,” to 10, “100% confident.” Intention asks how ready participants are to quit within the next month, from 0, “Not at all,” to 10, “100% ready.” The registry describes a higher score as a better outcome for all three.

These rulers are used to capture participants’ motivation, confidence, and readiness related to quitting. In general, such ratings can represent dimensions of a person’s stated orientation toward a behavior; they should not be treated as equivalent to the behavior itself. A rating of intention, for example, is not a direct count of quit attempts or a measure of abstinence.

The record specifies assessment at baseline, 2-week, and 1-month follow-up. It does not report the means, standard deviations, analyzed counts, or comparisons at those times. It also does not report whether the three ratings were analyzed separately or combined. Thus, the measure’s intended content and timing are described, but the registry record does not provide the outcome data needed to characterize changes or between-arm differences.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies a randomized, single-masked, parallel-group design. In general, random assignment is intended to make treatment groups comparable at the point of assignment by distributing both measured and unmeasured characteristics without systematic selection. It does not guarantee that groups will be identical, especially in a particular trial, and it does not replace reporting the actual analysis. The record does not describe sequence generation, allocation concealment, or the identity of the masked party, so those features cannot be assessed from the registry record.

A parallel-group design assigns participants to one intervention arm and follows the groups over time. Here, the two behavioral interventions differ in whether they include a distress-tolerance component. The primary measure is scheduled at baseline, 2-week, and 1-month follow-up. In general, repeated measurements can describe how outcomes vary over time, but an analysis needs to specify how it accounts for observations from the same participant. The model used for this trial is not reported in the registry record.

The outcome is continuous and is described using means and standard deviations. In general, a mean represents the average of observed values, while a standard deviation describes how spread out those values are around the mean. A mean alone does not show the distribution of individual scores, and a standard deviation is not the uncertainty of the mean or of a group comparison. The record does not post the means or standard deviations for the primary outcome.

For an intervention comparison, an analysis might estimate a difference between groups at a follow-up time, a difference in change from baseline, or a contrast across repeated observations. These approaches answer related but not identical questions and rely on different modeling choices. The registry record does not report which estimand or model was used, whether baseline values were included in an adjusted model, or how multiple assessment times were handled. None of these possible approaches should be assumed to have been used.

In general, a confidence interval quantifies the statistical uncertainty around an estimate under a specified model and sampling framework. Its width depends on factors including the amount of information in the data and the variability of the outcome. A narrow interval indicates greater precision than a wide interval, while neither interval width nor a point estimate alone establishes practical importance. No confidence intervals or other uncertainty estimates for the primary outcome are reported in the registry record.

The registry lists zero analyses. Thus there is no posted inferential result to interpret, and no basis for describing a statistically significant or non-significant primary comparison. The record also does not report a testing threshold, model assumptions, covariates, a missing-data method, or a prespecified hierarchy for outcome tests. A statistical plan cannot be reconstructed from the design description alone.

In general, continuous outcomes are often analyzed using methods that make assumptions about the outcome distribution and the relationship between observations. If a model assumes constant variance or a particular distribution, departures from those assumptions can affect uncertainty estimates and tests. Over-dispersion, in general, means variability is greater than a model expects; when that occurs, standard errors from an overly restrictive model may understate uncertainty. The Rulers for Smoking Cessation are described as continuous, but the record does not report distribution checks, model diagnostics, or any adjustment for over-dispersion. There is no basis to say whether these issues arose in this trial.

Missing data also affect interpretation of repeated measurements. In general, complete-case analysis uses only participants with observed measurements required by the analysis, whereas other methods can use partial records under stated assumptions. Different methods can yield different estimates when follow-up is incomplete. The registry notes that some participants did not complete selected follow-up assessments and that the overall number differs from the analyzed number. It does not report the numbers missing at each assessment, reasons for missingness, or the method used to address it.

The sample-size assumptions described for planning illustrations are not the trial’s own design justification. In general, a planning illustration based on an observed effect shows the sample size that might be required under stated assumptions to detect a chosen fraction of that effect. Such an illustration is not observed power and does not establish how the original trial was designed. The registry record does not report the trial’s sample-size justification or the effect size targeted during planning.

Finally, statistical evidence requires estimates and uncertainty information tied to a clearly described analysis population and method. Randomization and a stated endpoint are important design features, but they cannot substitute for those results. Because the registry record reports no analyses, the statistical methods actually used to produce a primary outcome conclusion are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome has three distinct components: motivation, confidence, and intention. It is measured at baseline, 2-week, and 1-month follow-up. Testing multiple components or time points can raise a multiplicity question: if several statistical tests are conducted, the chance of at least one apparently notable result can increase. In general, a prespecified testing hierarchy or an adjustment for multiple comparisons can help define how such results should be interpreted. The registry record does not report a multiplicity strategy or identify a single primary time-point comparison.

The record lists six outcome measures, but does not report their analysis results or explain how they relate in the analysis plan. It also lists zero analyses. Consequently, readers cannot determine which outcomes were tested, which tests were considered primary, or whether any adjustment for multiple testing was used. No claim about a positive or negative statistical finding can be evaluated.

For missing data, the registry states that the overall number differs from the analyzed number because participants did not complete selected follow-up assessments. The number of missing observations, their distribution across arms and time points, reasons for missingness, and analysis methods are not reported in the registry record. In general, missingness can affect both precision and the interpretation of an estimate, especially if participants with observed follow-up differ systematically from those without it.

The analysis populations are also not described. The record does not say whether analyses included all randomized participants, only those with observed data, or another defined group. It does not report how participants were handled if they did not complete the intervention. Without these details, the relationship between random assignment, follow-up completion, and any analyzed results cannot be assessed.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

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

The registry reports safety counts separately for the two intervention arms. For PFI for Smoking & Distress Tolerance, 57 participants are listed as at risk for serious adverse events and 57 for other adverse events; zero are listed as affected in either category, and deaths are recorded as zero. For PFI for Smoking Only, 64 participants are listed as at risk for serious adverse events and 64 for other adverse events; zero are listed as affected in either category, and deaths are recorded as zero. No serious adverse event terms are listed.

These are the adverse-event figures posted in the registry record. “At risk” is the denominator stated for the relevant category; it should not be confused with the total enrollment or with the number analyzed for the primary outcome. The record does not provide additional information about event definitions, collection procedures, duration of safety monitoring, or whether all events were captured in the same way.

In general, a recorded count of zero means no affected participants are listed in that record for the specified category; it does not establish that an event is impossible or that all potential harms have been ruled out. The figures also do not address the primary outcome comparison. Interpretation should remain limited to the counts and denominators recorded, with the unreported safety details kept in view.

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

The registry record establishes that a randomized, parallel-group behavioral trial compared a smoking-and-distress-tolerance feedback intervention with a smoking-only feedback intervention. It also identifies a primary outcome consisting of motivation, confidence, and intention ratings at baseline, 2-week, and 1-month follow-up. Those details describe the question the trial set out to examine.

The record does not report analyses or numerical results for that primary outcome. It therefore does not show whether scores changed over time, whether the groups differed, how large any difference was, or how precisely it was estimated. It cannot support a conclusion that either intervention improved or failed to improve motivation, confidence, or intention. The absence of posted results is not evidence that there was no effect; it means the effect cannot be evaluated from this registry record.

The measures are self-reported ratings related to quitting, not a direct report of smoking cessation. Even if numerical ratings were available, they would need to be interpreted according to what each question measures. A high intention rating, for example, would describe stated readiness, not necessarily subsequent smoking behavior. The registry record does not report primary outcome values or a smoking-cessation result.

The posted safety counts list zero serious adverse events, zero other adverse events, and zero deaths in each arm. These counts should be read as registry entries for the stated at-risk groups, not as a complete account of all possible safety outcomes. They do not establish the absence of risk, and they do not answer the primary statistical question.

In general, a trial’s design can make a comparison interpretable only when outcome data, analysis methods, and uncertainty are also reported. Here, the design and endpoint are described, but the key result information is not reported in the registry record. The appropriate statistical conclusion is therefore limited: the registry describes the intended comparison, but the magnitude, direction, and precision of its primary outcome findings are unavailable.

13. Why This Trial Matters Statistically

This trial is statistically interesting because its two interventions share a smoking-focused feedback approach and differ by the addition of distress-tolerance content. That design frames a focused comparison: whether a broader feedback package is associated with different ratings than smoking-only feedback. The contrast is easier to describe than a comparison of unrelated interventions, but interpreting it still depends on reported outcome estimates and their uncertainty.

The endpoint also illustrates why outcome definitions matter. Motivation, confidence, and intention are related but distinct concepts, each assessed with its own question. Treating them as interchangeable could obscure what a result means. The scheduled assessments at baseline, 2-week, and 1-month follow-up make timing part of the interpretation, while the missing analysis details prevent determining which time point or contrast was used.

The registry’s note about incomplete follow-up highlights a routine challenge in longitudinal clinical research: the enrolled group and the group contributing outcome data may not be the same. Reporting analyzed counts and missing-data methods is important for understanding how much information supports an estimate and what assumptions underlie it. Those details are not reported in the registry record.

More broadly, the record separates trial design from trial results. Randomization and a defined primary measure describe an intended method of comparison; they do not supply evidence about the size or precision of an effect. With zero analyses reported, the statistical value of the record is chiefly in clarifying the intervention contrast, outcome content, assessment schedule, and information that remains unreported. This distinction helps prevent a completed trial or a clearly stated research question from being mistaken for a reported finding.

14. Limitations

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

The most important trial-specific limitation in the registry record is the absence of primary outcome analyses. Although the primary measure and its assessment schedule are described, no group-level values, contrasts, uncertainty estimates, or tests are reported. The registry lists six outcome measures and zero analyses, so the posted record does not permit a statistical assessment of the trial’s primary comparison.

The record notes incomplete follow-up assessments and says the overall number differs from the analyzed number. It does not give analyzed counts by arm, outcome, or time point, nor does it describe reasons for missing measurements or how they were handled. This prevents assessment of how much follow-up information contributed to any analysis and whether the analysis population remained comparable across the randomized arms.

Important design and methods details are also absent. The registry does not report the randomization procedure, allocation concealment, who was masked, the statistical model, analysis population, multiplicity approach, or sample-size justification. The record does not describe intervention fidelity or adherence. These omissions limit assessment of internal validity and the interpretation of any unposted result.

The primary outcome is based on three self-reported ratings about quitting motivation, confidence, and intention. The registry does not report a direct cessation outcome in the primary result description, and it does not post the other outcome results. The stated ratings should therefore be understood as measures of reported motivation and readiness, not as proof of subsequent behavior.

The registry lists conditions but does not report detailed eligibility criteria or participant characteristics. Generalizability to a particular population cannot be judged from those condition labels alone. These limitations describe gaps in the registry record; they do not establish that the underlying study lacked methods or results that may be available elsewhere.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Personalized Feedback for Distress Intolerant Smokers — NCT03918031.
• Registry record last updated 2024-11-15; status last verified 2024-11.
• Results first posted 2024-11-15.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

NCT03918031, titled “Personalized Feedback for Distress Intolerant Smokers,” is listed as a completed, randomized, single-masked, parallel-group behavioral trial sponsored by the University of Houston. Enrollment is listed as 121. The study start date is 2019-07-15 and the primary completion date is 2021-10-24.

The comparison is between a one-session computer-delivered personalized feedback intervention addressing smoking and distress tolerance and a one-session smoking-only feedback intervention. The registered primary outcome is the Rulers for Smoking Cessation: ratings of motivation, confidence, and intention, assessed at baseline, 2-week, and 1-month follow-up.

The registry lists six outcome measures and zero analyses. Primary outcome results and statistical methods are not reported in the registry record. The record notes that some participants did not complete selected follow-up assessments. It lists zero serious adverse events, zero other adverse events, and zero deaths in each arm.