Sun Protection and Tanning Awareness in Rural Schools: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Sun Protection and Tanning Awareness in Rural Schools (NCT06694571), a na na study. The primary outcome is Sun Protection Index Scores - Weekday.

2. Clinical Question

In practical statistical terms, the study’s primary question is about within-participant change after an educational program, not a difference between intervention and control groups. A change score can describe whether participants’ reported sun-protection behavior shifted over the follow-up period. Without a comparison group, however, such a shift cannot by itself distinguish the program’s contribution from other influences, including ordinary changes over time or events outside the study.

The registry summary also says that interviews and surveys following initial implementation were intended to evaluate the program. The primary outcome listed in the record is a survey-based weekday score. The record does not report interview findings, nor does it report numerical results for the primary outcome. Thus, the question is clear, but the posted record does not provide a numerical answer.

3. Trial Design

STARS, or Sun Protection and Tanning Awareness in Rural Schools, is registered as a completed study sponsored by the University of Utah. The record gives a start date of 2024-10-14 and a primary completion date of 2025-03-08. It lists the phase as NA, allocation as NA, masking as none, and the study model as single group. The listed enrollment is 38.

The study evaluates a behavioral intervention: a skin cancer prevention educational presentation and activities. The registry description says that intervention components were adapted for rural high schoolers and would be co-implemented by the research team and participating school staff. Components include education, an action-planning exercise, and a risk-assessment activity, delivered during a single- or double-session in-class visit lasting up to 90 minutes.

This design collects outcome information from a group receiving the program but does not include a concurrent comparison arm. The registry itself flags that the record is not a randomized comparison and that the arms are not a like-for-like control comparison. Because there is no separate control group, the design can describe change over time in the studied group, but it cannot directly estimate how that change differs from what would have happened without the program.

The primary outcome is a weekday sun-protection index score, measured at baseline and one month. The record defines the outcome as the one-month value minus the baseline value. It also reports that 8 participants did not complete the one-month survey. The record lists two outcome measures and zero analyses. It does not report the statistical analysis plan, sample-size justification for the trial’s own design, interim analyses, or analysis populations.

The status is completed, but completion does not mean that numerical outcome findings are available in the registry record. The primary outcome’s baseline and follow-up summaries, change estimate, and measures of statistical uncertainty are not reported in the registry record. As a result, the design and intended measurement can be described, but the primary outcome’s observed magnitude cannot be assessed.

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: 8 participants did not complete the 1-month survey.

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 Sun Protection Index Scores - Weekday, measured over Baseline and One-month time points, up to one month.

The primary endpoint is titled “Sun Protection Index Scores - Weekday.” It is a continuous score intended to summarize the frequency of sun-protection items reported in surveys at baseline and at one month. The items use a 1-5 scale. The registry states that lower scores indicate less sun protection and higher scores indicate more sun protection. The endpoint is the value at one month minus the value at baseline.

A continuous average score can capture a range of reported behavior rather than reducing each participant’s responses to a simple yes-or-no category. Using the same measure at baseline and follow-up makes it possible to describe within-participant change. In general, a positive change on this defined scale would indicate a higher reported score at one month than at baseline, while a negative change would indicate a lower score. This interpretation concerns the direction of the score, not a demonstrated change in the study.

The endpoint is relevant to the program’s educational focus because it measures reported sun-protection practices. It is nevertheless a survey measure, not a direct observation of behavior or a measure of clinical disease. The record does not report the item-level results, baseline or follow-up means, standard deviations, or the mean change. It therefore does not show how much the score changed, how variable participants’ scores were, or how precisely any change was estimated.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous and is described as a mean score. A continuous measure can take a range of values, which allows the analysis to represent variation in reported sun-protection frequency. The registry defines the scale as an average of sun-protection items rated on a 1-5 scale and specifies that higher scores indicate more reported sun protection. The record does not describe the individual items or how item responses were handled if any were missing.

What does a change score represent?

The outcome is defined as the one-month score minus the baseline score. This is a within-participant change: each participant’s follow-up value is interpreted relative to that participant’s starting value. Across participants, a mean change would summarize the average of those individual changes among the participants included in the analysis. It is not the same as comparing the intervention group with a separate control group. No mean change is reported in the registry record, so the actual average direction and magnitude are unknown.

When the same people are assessed at two time points, the two scores are related rather than independent. An analysis of paired measurements should account for that relationship. In general, variability in change depends on how much participants’ scores vary and on how their baseline and follow-up scores move together. A standard deviation describes variation among observed scores or changes; it is not itself a measure of how precisely the group mean has been estimated. The registry lists standard deviation as the dispersion measure for the primary outcome, but does not report a value.

How should uncertainty be assessed?

A confidence interval is a statistical range intended to express the uncertainty around an estimate under a specified analysis. For a mean change, it would help readers judge which values are reasonably compatible with the observed data and model. A narrow interval would indicate greater precision than a wide interval, but interval width also depends on the analysis and the available data. No confidence interval or other uncertainty measure for the primary outcome is reported in the registry record.

A hypothesis test, if conducted, would address a prespecified statistical question under a stated model. A p-value is not the size of an effect, the probability that a hypothesis is true, or a measure of practical importance. It should be read together with the estimated change and its uncertainty. The record lists zero analyses and gives no test statistic or p-value. It is therefore not possible to describe statistical significance from the posted results.

What does the study design permit?

The registry identifies a single-group model, with allocation recorded as NA and masking as none. With no randomized comparator, an observed pre-to-post change would be descriptive of the measured group over time. It would not directly estimate a treatment-versus-control difference. General influences over the study period, measurement effects, and changes in who supplies follow-up data can also affect a before-and-after result. Statistical adjustment cannot by itself create the missing comparison group or establish that a change was caused by the program.

Blinding, when used in a trial, is intended to limit certain influences on care, assessment, or reporting. Masking is listed as none. Since the primary endpoint is survey-based, participants’ knowledge of the educational program may be relevant to how they report behavior; the record does not describe a method to assess or correct any reporting influence. This is a general consideration and not evidence that responses were biased.

Why can over-dispersion matter?

Over-dispersion is a general concern when observed variability is greater than a statistical model assumes. It can make standard errors too small if the model treats data as less variable than they are, which can in turn make intervals look too precise. The primary endpoint is a continuous mean score, and the registry does not report an analysis model or an over-dispersion assessment. Over-dispersion is therefore a general concept rather than a documented feature of this study’s results.

The record also mentions planning illustrations based on an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect defined as a stated fraction of the observed effect. Those assumptions describe planning illustrations, not the actual single-group study design. Sample-size figures under such assumptions would be planning quantities, not observed power and not evidence that the study had a particular ability to detect an effect. The record does not report the trial’s own sample-size justification, and it provides no observed effect estimate in the primary outcome results.

For time-to-event outcomes, general methods often count events and use assumptions about event occurrence over time. That is not the primary endpoint, which is a continuous mean score. The record does not report a time-to-event primary analysis. The most relevant statistical quantities for the listed endpoint would ordinarily include the score summaries at each time point, the mean within-participant change, the variability of that change, and an uncertainty interval, along with a transparent account of missing observations and the analysis population. These quantities are not reported in the registry 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("Skin Cancer Prevention Education")
n   <- c(30)
m   <- c(0.179)
sp  <- c(0.566)
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  Skin Cancer Prevention Education  30  0.179  0.566  -0.032  0.390

11. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures, but it does not report their full results or the analyses performed for them. It also lists zero analyses. A multiplicity plan specifies how conclusions are handled when more than one outcome or statistical test is considered. Testing multiple outcomes can increase the chance of at least one apparently unusual result, depending on the plan and the relationships among the tests. The registry record does not report whether a multiplicity adjustment or hierarchy of outcomes was specified, so no such approach can be inferred.

The primary endpoint is identified as the weekday sun-protection index score. Its stated timeframe is baseline and one month, up to one month. The record says that 8 participants did not complete the one-month survey. It does not report whether those participants contributed baseline data, whether any other measurements were missing, or how missing values were handled. Imputation, complete-case analysis, and other approaches are not reported in the registry record.

Missing follow-up data matter because the observed follow-up group may not fully represent everyone enrolled. If the likelihood of completing a survey is related to a participant’s score or experience, a summary among respondents could differ from the summary that would have been obtained with complete data. This is a general concern, not a claim about why participants missed the survey or the direction of any resulting bias. The record does not provide information to evaluate that possibility.

An analysis population defines which participants’ data are included for a particular estimate. For example, a report might state whether an analysis includes everyone enrolled, only those who completed follow-up, or another defined group. The registry does not report the primary outcome analysis population or a method for handling missing follow-up data. It also does not report interim analyses or a detailed statistical plan. Accordingly, the available record does not permit assessment of how those choices might affect the findings.

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.

The registry reports safety figures for the Skin Cancer Prevention Education group. It lists 38 participants at risk for serious adverse events and 0 affected. For other adverse events, it also lists 38 at risk and 0 affected. The number of deaths is 0. No top serious adverse-event terms are listed.

These are the event counts recorded in the registry, not a complete account of all possible experiences during the study. A zero count means that the record reports no affected participants in that category; it does not establish that no event could occur, or that the program has no risk. The figures also do not show the timing, duration, severity beyond the serious/non-serious categories, or any event-level detail.

Safety counts should be interpreted in the context of the study design and the number of participants reported at risk. The record describes a single-group educational program, not a comparison of adverse-event rates between intervention and control groups. With no comparator, the listed counts cannot establish whether events were more or less common than they would have been under another condition. The registry record does not report additional safety analyses.

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

The study record establishes that a rural-adapted skin cancer prevention education program was implemented as a behavioral intervention and that weekday sun-protection scores were intended to be assessed at baseline and one month. It also gives a sample enrollment of 38 and notes that 8 participants did not complete the one-month survey. These details describe the planned measurement and follow-up, not the observed primary outcome.

The record does not report numerical baseline or one-month scores, an average change, or an uncertainty interval. It therefore does not establish whether reported sun protection changed, how large any change was, or how precisely it was estimated. A completed study status does not substitute for posted results. Likewise, the educational content and the measurement plan do not in themselves demonstrate that the program produced a particular outcome.

Even if a numerical before-and-after change were reported, this single-group design would describe change over time among measured participants rather than a direct contrast with a control condition. Without a comparator, it would not isolate the program’s effect from other explanations for change. The registry record itself notes that it is not a randomized comparison and that the arms are not a like-for-like control comparison.

The score is a survey-based measure of reported frequency, not a direct measurement of observed behavior or a clinical endpoint. The record does not describe whether reported scores corresponded to actual sun-protection practices outside the survey, and no conclusion about clinical outcomes can be drawn from this endpoint alone.

The safety figures report zero serious adverse events, zero other adverse events, and zero deaths among the reported group counts. They are useful as registry entries but should not be read as proof that every possible adverse experience was absent. Taken together, the record gives useful information about study design, the intended behavioral measure, follow-up, and reported safety counts. It does not provide enough outcome information to determine the observed primary result or to make a causal claim about the program.

14. Why This Trial Matters Statistically

This study raises practical statistical questions common in school-based behavioral research: how to measure change in reported behavior, how to interpret a before-and-after score, and how missing follow-up responses affect the available evidence. The registry defines a continuous weekday sun-protection score and a specific change direction, making the intended estimand understandable. At the same time, the absence of posted numerical results means readers cannot evaluate the estimated change or its precision.

The single-group design is an important part of the statistical interpretation. A within-group comparison can show how scores differ between baseline and follow-up among those observed, but it does not provide the counterfactual comparison needed to separate program-related change from other changes over time. Recognizing that boundary helps keep descriptive evidence distinct from a causal estimate.

Follow-up completeness is also central. The record notes that 8 participants did not complete the one-month survey, while not reporting the missing-data method or the analysis population. Reporting those details alongside outcome estimates would help readers understand who contributed to the result and how sensitive conclusions might be to incomplete follow-up.

Finally, the registry’s planning assumptions should not be confused with the trial’s design or results. Planning illustrations can help explore what sample sizes might be associated with specified assumptions, but they are not observed power and do not replace reporting an effect estimate with uncertainty. For this study, the primary statistical need is a transparent result for the defined score change, accompanied by clear information about missing data and analysis choices. Until those results are reported, the registry supports understanding the question and design, but not quantifying the answer.

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 for interpreting this study is that numerical primary outcome results are not reported in the registry record. There is no baseline mean, one-month mean, mean change, standard deviation, confidence interval, or statistical test result to assess. The record lists zero analyses, so the magnitude, direction, and precision of the primary outcome cannot be described.

The single-group model provides no concurrent control group. As a result, a before-and-after change, if reported, could not be directly contrasted with change under a separate condition. This limits causal interpretation. The study is also listed with masking as none, and the primary endpoint is survey-based; the record does not report how participant awareness or response behavior was assessed.

Follow-up was incomplete: 8 participants did not complete the one-month survey. The record does not report the missing-data method, whether baseline information was available for those participants, or which participants were included in an outcome analysis. It is therefore not possible to assess how incomplete follow-up may have influenced an estimate.

The registry describes the primary measure as an average of sun-protection items on a 1-5 scale, but does not give item-level details or additional information about the score’s construction. The record does not report further participant characteristics or interview findings. It lists two outcome measures, but does not provide a multiplicity plan or full results for those measures. These limitations concern what can be learned from the registry record; they do not establish that unreported procedures or information were absent from the conduct of the study.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Sun Protection and Tanning Awareness in Rural Schools — NCT06694571.
• Registry record last updated 2026-04-03; status last verified 2026-03.
• Results first posted 2026-04-03.
• 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

STARS is a completed, single-group behavioral study of skin cancer prevention education for rural high schoolers, sponsored by the University of Utah. The registry lists 38 enrolled participants, no masking, and a primary weekday sun-protection index score assessed at baseline and one month. The intervention description includes education, action planning, and risk assessment delivered by the research team and participating school staff during a single- or double-session visit lasting up to 90 minutes.

The primary outcome is defined as the one-month score minus the baseline score on a 1-5 measure, with higher scores indicating more sun protection. The record notes that 8 participants did not complete the one-month survey. It lists zero analyses and does not report numerical primary outcome results, an analysis plan, or a missing-data method. Safety figures list 0 serious adverse events, 0 other adverse events, and 0 deaths among 38 participants at risk. The record does not include a randomized control comparison, so it cannot provide a direct intervention-versus-control estimate.