Daily Living Skills Intervention for Adolescents With Autism Spectrum Disorder: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Daily Living Skills Intervention for Adolescents With Autism Spectrum Disorder (NCT03984487), a randomized na study. The primary outcome is Vineland Adaptive Behavior Scales, 3rd Edition.

2. Clinical Question

The study was described as a pilot randomized controlled trial. Its summary says the objective was to examine how participation in STRW affects proximal outcomes, and to explore links with social skills, executive functioning, and parenting factors. These are aims stated in the registry, not reported findings. The record also does not specify which particular contrast or time-point comparison was prespecified as the primary statistical test.

3. Trial Design

The registry describes a randomized, parallel-group trial with single masking. Participants were assigned to STRW, a daily living skills intervention, or PEERS, a social skills intervention. The identity of the party or parties who were masked is not reported in the registry record. The record lists the trial as completed and gives an enrollment of 73.

The study is identified as a pilot RCT for adolescents with autism spectrum disorder in the last 2 years of high school. Its brief summary describes a larger sample size of n = 72, while the enrollment field lists 73. The reason for this difference is not reported in the registry record; these figures should not be treated as interchangeable measures of participants included in an outcome analysis. The number contributing data to the primary measure is not reported.

The interventions are described by name and broad purpose, but detailed information on their content, delivery schedule, provider training, adherence, crossover, or co-interventions is not reported in the registry record. The registry does not identify the allocation sequence method or explain how concealment was maintained. Random assignment is intended to make groups comparable at the start of a study, but the record does not provide baseline characteristics with which to assess that balance.

The listed primary outcome is the Vineland Adaptive Behavior Scales, 3rd Edition, Daily Living Skills domain raw score. The stated timeframe is 4 months from baseline to post-intervention. The registry does not give the date of each participant’s assessment, the exact assessment window, or a numerical group comparison. It also does not report a statistical analysis plan or analysis results. Therefore, the design features can be described, but the effect of assignment on the primary outcome cannot be estimated from 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.

Before assignment: We had several screen fails, which we compensated for by enrolling above our target number for completion. Randomization was stratified based on IQ (i.e., IQ\>85 and IQ\<85).

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.

Population: STRW: 36 allocated to intervention, 2 lost to follow up before intervention completion, 3 lost to follow up post-intervention (31 analyzed). PEERS: 37 allocated to intervention, 7 lost to follow up before intervention completion (30 analyzed).

6. Primary Endpoint

The registry lists the primary outcome as Vineland Adaptive Behavior Scales, 3rd Edition, measured over 4 months (from baseline to post-intervention).

The primary measure is the Daily Living Skills domain raw score from the Vineland Adaptive Behavior Scales, 3rd Edition (VABS-3). The registry describes this as a standardized measure of adaptive behavior, with Communication, Daily Living Skills, and Socialization domains. The Daily Living Skills domain includes Personal, Domestic, and Community subdomains, with items corresponding to goals targeted in STRW.

The recorded outcome is the average, or mean, Daily Living Skills domain raw score at baseline and post-treatment. Its stated timeframe is 4 months from baseline to post-intervention. The registry gives the possible total raw-score range as 0 to 286 and states that higher scores indicate greater independence in overall daily living skills. These details explain what a score is intended to represent; they do not indicate how participants in either group scored.

Using a standardized measure can support consistent assessment across participants and time points. A domain focused on daily living skills is relevant to an intervention aimed at those skills, while the raw score may also reflect individual differences in the specific abilities captured by the measure. The registry does not report whether a clinically meaningful change threshold was defined, how the measure was administered, or whether assessors were masked. Most importantly, it does not report baseline or post-treatment means, standard deviations, or an analyzed treatment contrast. The endpoint’s measurement description is available, but its observed results and their uncertainty are not reported in the registry record.

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 with a standard deviation. It does not report the observed means or standard deviations, nor an analysis comparing the groups. The explanations below describe general statistical concepts; they are not a description of an analysis confirmed for this trial.

What does a mean and standard deviation describe?

In general, a mean is the arithmetic average of observed scores. It describes the center of a distribution, but does not show how widely individual scores vary. A standard deviation describes the spread of observations around the mean. Together, they give a concise description of a continuous outcome, but do not by themselves establish whether groups differ or whether a difference is precise.

For this trial, the score is a raw score for the VABS-3 Daily Living Skills domain. The registry states that higher scores correspond to greater independence and gives a raw-score range of 0 to 286. This helps define the scale’s direction and range. It does not provide the actual group means, the standard deviations, or the distribution of scores. Without those results, readers cannot assess the observed levels, variability, or overlap between groups.

What would a treatment contrast mean?

In general, a treatment contrast is a numerical estimate of how outcomes differ under the compared assignments. The interpretation depends on the exact contrast: it might compare group means at post-treatment, compare changes from baseline, or estimate a post-treatment difference while accounting for baseline scores. These approaches answer related but not identical questions and may rely on different assumptions.

The registry says that mean scores were reported at baseline and post-treatment, but it does not state the primary contrast or give an analysis estimate. It also does not report a confidence interval. In general, a confidence interval describes a range of values compatible with the data and statistical model, conveying uncertainty around an estimate. It is not a guarantee that the true effect lies within that range. Since no estimate or interval is reported, the precision of any group difference cannot be evaluated.

Why does the analysis plan matter?

In general, a prespecified analysis plan clarifies the outcome, time point, treatment contrast, model, handling of baseline measurements, and approach to missing data. This helps readers distinguish the planned primary analysis from exploratory analyses and assess whether the reported estimate answers the study question. The statistical plan is not reported in the registry record, so those choices cannot be attributed to this trial.

Random allocation is intended to reduce systematic differences between groups at assignment. In general, randomization does not guarantee that every characteristic is balanced, particularly in a pilot study, and it does not prevent bias from missing outcomes, deviations from assigned intervention, or outcome measurement. The registry does not give baseline characteristics, allocation concealment details, or an account of departures from assignment. The effect of these issues on the outcome cannot be assessed from the record.

What does the planning illustration represent?

In general, sample-size planning asks how many participants would be needed to detect an assumed effect with a chosen statistical procedure and target power. A planning illustration based on an observed effect is conditional on that effect being a suitable planning value. It is not observed power and does not demonstrate that the trial had enough information to estimate the effect precisely. The record describes the illustration as using a two-sided significance level of 0.05, equal allocation, a normal approximation, and effects expressed as stated fractions of the observed effect. It says that non-time-to-event planning figures refer to participants per arm.

Those assumptions describe the planning calculation, not the trial’s reported analysis. No observed effect or numerical planning estimates are reported in the registry record, and the registry does not give the trial’s own sample-size justification. The illustration cannot be used to infer that the intervention had a particular effect or that the study achieved a particular power.

Why can over-dispersion matter?

In general, over-dispersion occurs when observed variation is greater than a statistical model assumes. When a model underestimates variability, its standard errors may be too small and its confidence intervals too narrow. A suitable model or variance adjustment can address this problem when the data and outcome type warrant it. The primary endpoint in this trial is described as a continuous mean, and the registry does not report a model, an over-dispersion assessment, or an analysis that would permit evaluation of this issue. It should not be assumed that over-dispersion was relevant or that any correction was applied.

The registry lists zero analyses. That means the record has no analysis entry for the outcome; it does not prove that no analysis took place outside the registry. In the absence of reported methods and results, statistical interpretation must remain at the level of general principles and the endpoint description.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure, but the primary measure is described at baseline and post-treatment. The record also indicates that the primary outcome has several categories or time points and was not reduced to one comparison. It does not identify a single primary contrast or report estimates for the different categories or time points. Therefore, the endpoint listing alone does not establish which result would answer the main statistical question.

When several outcomes, domains, time points, or comparisons are examined, the chance of finding an apparently notable result can increase. In general, a multiplicity plan identifies which comparisons are confirmatory and whether adjustment or another strategy will be used. The registry does not report such a plan or state whether any adjustment was made. It also does not identify secondary analyses or distinguish confirmatory results from exploratory ones.

Missing-data information is also absent. The registry does not report the number with outcome data at baseline or post-treatment, reasons for missing assessments, or the statistical method used to address missing values. In general, missingness can affect both the precision and interpretation of an estimate, especially if the likelihood of missing data relates to participants’ outcomes or group assignment. The information needed to assess that possibility is not reported in the registry record.

The record does not state whether the primary analysis included all randomized participants, only those who completed their assigned intervention, or another analysis population. It also does not describe how participants who changed or did not complete their assigned intervention were handled. These details should not be inferred from enrollment or from the study’s completed status. Without a stated analysis population, missing-data approach, and multiplicity strategy, the robustness and scope of any treatment comparison cannot be evaluated from the registry record.

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.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: self injury (3.2%), inpatient stay (3.2%).

The adverse-event figures list 31 participants at risk in STRW and 30 in PEERS. One participant in STRW is recorded as affected by a serious adverse event, compared with none in PEERS. The listed deaths are zero in both groups. These counts describe the registry’s safety entries; they do not establish the cause of an event or whether it was related to an intervention.

“Self Injury” and “Inpatient stay” are each listed among the top serious-event terms at 3.2%. The record does not clarify how those terms correspond to the affected-participant counts, whether they refer to distinct participants or events, or how events were judged related to treatment. No other adverse events are recorded as affecting participants in either group. The timeframe for safety monitoring and the rules used to classify seriousness are not reported in the registry record.

Small event counts are descriptive and can be imprecise. The registry figures should not be read as a comparative safety analysis, and they do not establish that an event was caused by STRW or PEERS. They also do not describe the full range of possible harms beyond what was entered in the record. The absence of a recorded event in a group is not evidence that no such event could occur.

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

The registry establishes that a randomized, parallel-group pilot trial compared STRW, a daily living skills intervention, with PEERS, a social skills intervention. It identifies adolescents with autism spectrum disorder in the last 2 years of high school as the target population, lists an enrollment of 73, and describes the VABS-3 Daily Living Skills domain raw score as the primary measure. The outcome was intended to be assessed at baseline and post-treatment over 4 months.

The record does not report the observed scores, group means, standard deviations, treatment contrast, confidence interval, or p-value. It therefore does not show whether scores changed, how they differed between groups, or how precisely any difference was estimated. The absence of these results should not be interpreted as evidence of no difference, nor as evidence of a difference. The registry’s description of the intervention’s goals is not an outcome finding.

The stated score range and direction help explain the measure, but a score change alone would not establish the practical importance of a result. The registry does not report a threshold for meaningful change or an analysis connecting score changes to later independence. It also does not report results for other measures mentioned in the study summary, such as goal attainment scaling or self-report measures.

The trial’s completion status and safety entries provide information about the record, but do not substitute for efficacy or feasibility results. The serious adverse-event counts are descriptive and do not establish causality. The planning illustration is not observed power and cannot supply a missing treatment effect.

Accordingly, the supported conclusion is limited: the registry describes a randomized pilot comparison and the intended primary outcome, but does not report the analysis needed to quantify or interpret a difference in daily living skills between the intervention groups. Any broader conclusion about intervention effects, safety, or generalizability would go beyond the posted results.

13. Why This Trial Matters Statistically

This trial raises a useful statistical question because the intervention aims to affect a specific adaptive-behavior domain, and the registry identifies a standardized measure with content corresponding to daily living skills goals. Connecting the intervention’s target to an explicitly described outcome makes the intended measurement clear. The measure’s direction is also stated: higher raw scores indicate greater independence in overall daily living skills.

The randomized, parallel-group design is relevant to estimating the effect of assignment to the two programs. Randomization can support a fair comparison when allocation and follow-up are implemented well and analyzed appropriately. The registry, however, does not report enough detail to assess allocation procedures, baseline balance, missing outcomes, or the statistical comparison. A design label alone cannot demonstrate that the resulting estimate is unbiased or precise.

The study is identified as a pilot, making the distinction between feasibility and treatment-effect estimation especially important. In general, pilot evidence can help inform later study design, but an observed effect from a pilot may be uncertain. The registry does not report feasibility findings, a treatment-effect estimate, or its uncertainty. It describes a planning illustration based on an observed effect, but that is not observed power and cannot replace a transparent analysis.

There is also a clear need to specify the target contrast when assessments occur at baseline and post-treatment and the outcome record includes multiple categories or time points. A prespecified comparison, analysis population, and missing-data strategy would help readers understand exactly what is being estimated. These statistical details are not reported in the registry record. The entry therefore makes the trial’s intended question visible while leaving its empirical answer unresolved.

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 main limitation for statistical interpretation is that the registry does not report primary-outcome results or an analysis of the VABS-3 Daily Living Skills domain. No group means, standard deviations, treatment estimate, confidence interval, or p-value are included. As a result, neither the magnitude nor the precision of a group difference can be assessed.

The registry describes mean scores at baseline and post-treatment, but does not specify the primary contrast or explain how the repeated measurements were analyzed. It notes that the outcome has several categories or time points and was not reduced to one comparison. The record does not identify a prespecified comparison, report results by time point, or explain how multiplicity was handled.

Enrollment is listed as 73, whereas the study summary describes a larger sample size of n = 72. The difference is not explained in the registry record. Neither figure provides the number of participants with complete primary-outcome data or the size of the analysis population. Missingness, reasons for missing data, and methods for handling it are not reported.

Further limitations include the absence of a statistical analysis plan, allocation-concealment details, baseline characteristics, intervention adherence information, and identification of who was masked. The record does not state whether a clinically meaningful change threshold was defined or how outcomes beyond the primary measure were analyzed. Serious adverse-event entries lack context on monitoring duration and causal assessment. These omissions limit evaluation of bias, precision, applicability, and safety interpretation; they do not show that the omitted procedures or analyses were not conducted elsewhere.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Daily Living Skills Intervention for Adolescents With Autism Spectrum Disorder — NCT03984487.
• Registry record last updated 2024-07-23; status last verified 2024-07.
• Results first posted 2024-07-23.
• 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

The registry describes a completed, randomized, single-masked, parallel pilot trial of STRW versus PEERS for adolescents with autism spectrum disorder in the last 2 years of high school. Enrollment is listed as 73. STRW is described as a daily living skills intervention, and PEERS as a social skills intervention.

The primary measure is the VABS-3 Daily Living Skills domain raw score, with means described at baseline and post-treatment over 4 months. Higher scores indicate greater independence, and the raw-score range is 0 to 286. The registry lists one outcome measure and zero analyses. It does not report numerical primary-outcome results, the statistical comparison, missing-data handling, or an analysis population.

The safety record lists one serious adverse-event-affected participant in STRW and none in PEERS, with zero deaths in both groups. The registry does not establish event causality. The result record describes the trial’s design and intended measurement, but leaves the primary treatment comparison unreported.