Effects of Smoking State on Decision Making: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effects of Smoking State on Decision Making (NCT04826276), a na na study. The primary outcome is Effort Based Decision Making.

2. Clinical Question

The study title focuses on the effect of smoking state on decision making, and the official title specifies effort-based decision making. Participants were to complete behavioral and neuroimaging assessments after smoking as usual and after overnight abstinence. The primary outcome listed in the record is behavioral: the number of high-effort selections over an approximately 2-week timeframe. The record does not define the decision task in further detail, describe the effort levels, or explain how a high-effort choice was operationalized. The result therefore cannot be interpreted as a quantified difference in decision making from the registry information available. It is also not possible to determine whether any observed contrast would reflect smoking state, assessment order, or other influences without the actual results and analysis details.

3. Trial Design

The registry describes a completed, single-group study sponsored by Wake Forest University Health Sciences. Enrollment is listed as 5. The study began on 2022-09-01, and primary completion is listed as 2023-03-28. The record lists phase as NA, allocation as NA, and masking as NONE. It does not describe a parallel randomized treatment comparison.

The study assessed smoking abstinence and smoking satiety. The arm descriptions identify two sequences: “Withdrawn Then Satiated” and “Satiated Then Withdrawn.” One description says assessment after 12+ hours without smoking occurred before assessment after smoking as normal; the other says smoking as normal was assessed first, before assessment after 12+ hours of abstinence. These descriptions indicate that assessment order was relevant, but the registry record does not explain how participants were assigned to the sequences or whether sequence order was randomized. Allocation is listed as NA, and the record explicitly does not support treating the arms as a like-for-like control comparison.

Because the study is single group and the smoking states are assessed in relation to one another, it differs from a design in which separate randomized groups receive different assigned treatments. A comparison of states within participants can be informative, but interpretation depends on the actual analysis and on how order and repeated observations are handled. The registry record does not report those analysis details. It also does not provide a protocol description, sample-size justification, or information about interim analyses. The listed completion status is COMPLETED, but that status does not itself establish that outcome results were posted.

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

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 Effort Based Decision Making, measured over approximately 2 weeks.

The primary endpoint is “Effort Based Decision Making,” measured as the number of high-effort selections. It is a continuous outcome summarized by a mean and standard deviation, according to the registry record. In general, a count of selections can describe how often participants choose an effortful option during a decision task. Comparing the measure across smoking states could therefore describe a behavioral difference in task choices under those states.

The registry lists an approximately 2-week timeframe. It does not provide additional detail about the task, the number of opportunities to make a selection, or the exact timing of each assessment. Those details matter when interpreting a selection count, because the meaning of a count depends on the task and how it is administered. The record also does not report the observed mean, standard deviation, or a comparison estimate for this endpoint. Thus, the outcome definition is available, but its observed magnitude and precision cannot be assessed from the registry record. The endpoint alone does not establish why a participant chose a high-effort option, nor does it indicate a clinical benefit or harm.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies a continuous primary outcome summarized as a mean and standard deviation. These summaries have different roles. A mean describes the average outcome in the observations being summarized; a standard deviation describes the spread of those observations around their mean. Neither one by itself gives the uncertainty in a comparison between smoking states. The registry record does not report the numerical summaries for the primary outcome.

What a comparison would estimate

In general, a comparison of the two smoking states could be expressed as a difference in average high-effort selections. The estimate would describe the observed contrast under the study's assessment conditions, not automatically a causal effect of smoking state. In a nonrandomized, single-group study, interpretation depends on the design and analysis, including how repeated assessments and assessment sequence are handled. The registry record does not report the estimated contrast or specify the method used to estimate it.

A confidence interval, in general, gives a range of values compatible with the data and the statistical model at a stated confidence level. Its width conveys precision: a narrower interval indicates greater precision than a wider interval. An interval also shows which effect directions and magnitudes remain compatible with the data. No confidence interval for the primary outcome is reported in the registry record, so precision cannot be evaluated from an interval.

Repeated assessments and order

The study description includes assessments after smoking as usual and after at least 12 hours of abstinence, with the sequence descriptions indicating different orders. When the same participants contribute observations under more than one condition, those observations may be correlated. General methods for paired or repeated measurements account for this dependence rather than treating every observation as independent. However, the registry record does not state the exact analysis population, whether every participant completed both assessments, or how any within-participant relationship was modeled. It would be inappropriate to assume a specific paired analysis solely from the design description.

Order can also affect a comparison. For example, practice, fatigue, or changes over the assessment period are general possibilities in repeated assessments; the record does not say whether any of these occurred in this study. The sequence labels identify an order contrast, but the record does not explain sequence assignment or report an analysis of order. The approximately 2-week timeframe provides a broad outcome timeframe, not enough detail to determine the interval between individual assessments.

Variation and over-dispersion

The primary measure is a number of selections, while the registry classifies it as a continuous outcome and specifies a mean with standard deviation. As a general matter, count outcomes can have distributions that differ from a normal distribution, especially when values are concentrated or unusually variable. Over-dispersion means that the observed variability is greater than a model assumes. If present, it can make standard errors from an unsuitable model too small and confidence intervals too narrow. This is a general methodological consideration, not a claim about the study's data. The record does not include the outcome distribution or enough analysis information to assess whether over-dispersion was relevant.

The sample-size assumptions mention a normal approximation. In general, a normal approximation uses a model based on a bell-shaped sampling distribution to estimate planning requirements or conduct inference. Whether that approximation is appropriate depends on the data and analysis context. The registry's statement that a planning illustration is based on a fraction of the observed effect describes an assumption for planning, not a result about the endpoint. The numerical illustration is not reported in the registry record. It should not be interpreted as observed power, and no study-specific sample-size justification is reported.

Significance and multiplicity

A significance test, in general, assesses how compatible data are with a specified null hypothesis under a statistical model. A p-value does not measure the probability that a hypothesis is true, nor does it convey the size or practical importance of an effect. The planning description names a two-sided significance level of 0.05, but the record does not report a primary-outcome test or p-value. That planning assumption should not be mistaken for a reported analysis threshold or a result.

Multiplicity arises when several outcomes, comparisons, or analyses are examined. Repeated testing can increase the chance of a false-positive finding unless the analysis plan addresses it. The registry lists 2 outcome measures and 0 analyses, but it does not report a multiplicity strategy. It is not possible to infer which outcomes were tested, whether any adjustments were made, or whether there were additional analyses beyond the registry listing.

Finally, sample-size planning and outcome interpretation answer different questions. A planning illustration asks what sample size might be required under stated assumptions; it does not show what the observed data demonstrated. The registry record does not report numerical sample-size illustrations, observed estimates, or uncertainty measures. Consequently, general statistical principles can explain what such quantities would mean, but cannot supply a study result that is absent from the record.

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("Withdrawn Then Satiated", "Satiated Then Withdrawn")
n   <- c(2, 3)
m   <- c(29.5, 18.3)
sp  <- c(16.5, 2.62)
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  Withdrawn Then Satiated  2  29.500  16.500  -118.747  177.747
CARM  Satiated Then Withdrawn  3  18.300  2.620  11.792  24.808

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 2 outcome measures and 0 analyses. It does not report a multiplicity plan, such as how conclusions would account for testing more than one outcome or making multiple comparisons. Multiplicity matters in general because conducting several statistical tests can increase the chance of a false-positive result if the testing strategy is not considered. The available record does not establish how many comparisons were performed in practice or whether any adjustment was used.

Missing-data handling is not reported in the registry record. There is no account of missing endpoint observations, withdrawals from assessment, reasons for missingness, or a method used to handle incomplete data. The record also does not define the analysis population or state whether analyses included all enrolled participants or only those with observations under both smoking states. With enrollment listed as 5, these details would be relevant to understanding how many observations contributed to any estimate, but the outcome results and analysis population are not reported.

These absences limit assessment of both the validity and precision of a result. A complete-case analysis, an imputation method, and other approaches rely on different assumptions; none can be attributed to this study from the registry record. Likewise, the record does not say whether the stated primary outcome was analyzed according to a prespecified plan. No conclusion about multiplicity control or missing-data bias can be drawn from the outcome description alone.

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 5% reporting threshold.

The registry reports serious adverse event figures for the two sequence groups. In “Withdrawn Then Satiated,” serious events were reported for 0 of 2 participants at risk. In “Satiated Then Withdrawn,” serious events were reported for 0 of 3 participants at risk. Deaths were reported as 0 in both groups. These are the registry's recorded figures; they do not establish that no event could have occurred outside the record's reporting scope.

The record also reports 0 other adverse events for 2 participants at risk in the “Withdrawn Then Satiated” group, and 0 for 2 participants at risk in the “Satiated Then Withdrawn” group. The at-risk counts for other adverse events are not the same as the serious-event counts listed for those groups. The registry does not provide serious adverse event terms, and it lists no top serious-event terms.

With small recorded at-risk groups, zero reported events should be read as an observation in those groups, not as proof that the risk is absent. These figures do not compare randomized groups, and they do not provide a basis for a broader safety conclusion. The registry record does not describe the adverse-event collection procedures or observation periods in further detail.

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

The record's central contribution is a description of a study question: effort-based decision making was assessed in adult smokers after smoking as usual and after overnight abstinence. It identifies the primary endpoint as the number of high-effort selections and gives an approximately 2-week timeframe. It also records the study as completed, with enrollment of 5, and describes sequences involving the two smoking states.

What the record does not establish is the observed result. There is no reported mean, standard deviation, contrast, confidence interval, or primary-outcome test. Therefore, it cannot show from the registry information whether the number of high-effort selections was higher, lower, or similar in one state compared with the other. It also cannot establish how precise such a comparison would be.

Even if an outcome contrast were available, its interpretation would depend on study conduct and analysis. This was listed as a single-group study with allocation NA, not a randomized comparison. The sequence descriptions make assessment order relevant, but the record does not say how order was assigned or accounted for. A difference between assessments would not, by itself, distinguish an effect of smoking state from order, time, or other influences.

The endpoint is a measure of task selections, not a direct measure of every aspect of decision making. The registry does not detail the task or define what each high-effort selection represents beyond its count. The record also does not report participant characteristics beyond describing adult smokers. General conclusions beyond the stated behavioral outcome would therefore go beyond the information available.

The adverse-event listings show zero reported serious events and zero deaths in the recorded groups, with the stated at-risk counts. Those observations are limited to the participants and reporting in the registry. They do not establish an absence of risk. Overall, the record is informative about the study's intended comparison and some design features, but it does not contain the outcome results needed to characterize the primary endpoint.

14. Why This Trial Matters Statistically

Statistically, this study illustrates the distinction between a registered research question and a reported result. The record specifies an outcome, a mean and standard deviation summary, an assessment timeframe, and a small enrollment. Those details identify what the investigators intended to measure, but they are not enough to evaluate an effect or its uncertainty. Without posted endpoint results, readers cannot assess magnitude, direction, or precision.

The design description also highlights why comparison structure matters. The registry identifies a single-group study with two smoking states and sequence labels rather than a randomized control comparison. Repeated assessments can provide information about how an outcome varies across conditions, but valid interpretation depends on within-participant dependence and assessment order. The registry record does not state how these were addressed analytically. Recognizing that limitation prevents a planned contrast from being mistaken for a randomized treatment effect.

The outcome itself raises useful general methodological questions. A number of selections is a count-like measure, while the registry identifies it as continuous and summarizes it with a mean and standard deviation. Understanding the distribution and variability would help assess whether the chosen model and its assumptions fit the observations. The record does not provide those data or the analysis method, so no study-specific judgment about model adequacy is possible.

Finally, the listed planning assumptions should be kept separate from evidence about observed outcomes. A normal approximation, equal allocation, a two-sided significance level of 0.05, and an effect fraction are planning concepts; they do not establish that the study had adequate power or that any effect was detected. The record's missing analyses and results mean that the statistical importance of the study lies chiefly in clarifying what information would be needed for interpretation, not in supporting a conclusion about the endpoint.

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.

Enrollment is listed as 5, limiting the amount of information that could be available for estimating variability or comparing smoking states. The registry record does not report the number of participants who completed each assessment or the number contributing to the primary outcome. The group-specific at-risk counts in the adverse-event listing do not substitute for an analysis population description.

The study is described as single group, with allocation NA and masking NONE. The registry explicitly cautions that the arms are not a like-for-like control comparison. The sequence descriptions indicate that assessment order differed, but random assignment of sequence and methods for handling order are not reported. This limits causal interpretation of any contrast between states.

The record does not provide the primary endpoint results, statistical analysis, confidence interval, or p-value. It also does not describe the decision task in enough detail to assess the meaning or range of the high-effort selection measure. Missing-data procedures, multiplicity handling, and a sample-size justification are not reported in the registry record. Although the record gives a planning-assumption description, numerical planning results are not reported. These gaps prevent assessment of the outcome's magnitude, precision, model fit, and robustness.

The registry lists the study as completed, but completion status does not resolve these reporting limitations. The safety figures are also based on small recorded groups and do not establish absence of risk. These limitations are specific to what the registry record reports; they do not imply that unreported procedures or analyses were not conducted.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Effects of Smoking State on Decision Making — NCT04826276.
• Registry record last updated 2026-05-01; status last verified 2022-09.
• Results first posted 2026-05-01.
• 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 identifies NCT04826276 as “Effects of Smoking State on Decision Making,” with an official title focused on effort-based decision making. Wake Forest University Health Sciences is listed as sponsor. The study is marked COMPLETED, with enrollment of 5, a start date of 2022-09-01, and primary completion on 2023-03-28. Phase and allocation are listed as NA, masking as NONE, and the model as SINGLE GROUP.

Adult smokers were assessed after smoking as usual and after 12+ hours of abstinence. The primary outcome is the number of high-effort selections, summarized as a mean and standard deviation over an approximately 2-week timeframe. The registry lists 2 outcome measures and 0 analyses. It does not report the primary outcome results, analysis method, missing-data handling, or multiplicity plan. Serious adverse events and deaths are recorded as 0 in both listed sequence groups. The record's design cautions against treating those sequences as a like-for-like control comparison.