Developing Inclusive Youth: Promoting Intergroup Friendships and Inclusive Classrooms in Childhood: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Developing Inclusive Youth: Promoting Intergroup Friendships and Inclusive Classrooms in Childhood (NCT05619523), a randomized na study. The primary outcome is School Belonging Scale.

2. Clinical Question

The trial asks whether a classroom program designed to encourage positive peer relationships and reduce prejudice and bias changes children’s experiences and attitudes. The primary result reported in the registry record concerns perceived school belonging, measured one week after the intervention. The broader aims described in the record include prejudicial attitudes, intergroup friendships, differences related to grade, gender, and ethnicity, and teachers’ attitudes and comfort discussing social inclusion and exclusion.

The primary comparison is narrower than the trial’s broader aims: it concerns school belonging, not every outcome mentioned in the study summary. The record lists 12 outcome measures, but the posted results include the School Belonging Scale as the primary outcome and do not include posted secondary results. The target population and setting also matter when interpreting the finding: it concerns children in the specified elementary-grade classrooms, rather than all children or all school contexts.

3. Trial Design

The study is described as a randomized, parallel-group trial with no masking. The registry record lists 885 participants as enrolled and marks the study completed. The reported arms are DIY Tool Classrooms, with 522 participants, and Business As Usual Classrooms, with 363 participants. Random allocation means the study assigned classrooms or participants to comparison groups by chance, although the registry record does not specify the precise unit of randomization in the details used for this result. No masking means that the study is not described as blinded.

The intervention was behavioral and classroom-based. Children used the online DIY tool, and a teacher led a discussion connected to each scenario. The summary describes student use of a Chrome notebook and headphones, followed by a classroom discussion. It also describes the program as occurring once a week for eight weeks. The intervention-arm description says that students completed a pretest and posttest survey and worked through eight scenarios. The control arm followed a business-as-usual plan without an alternative program and completed pretest and posttest measures in the same weeks.

The primary outcome was assessed one week following completion of the eight-week intervention. The registry describes the measure as a mean score on the School Belonging Scale. Although the study summary mentions a pretest and posttest, the posted primary result is an arm comparison at the specified post-intervention timeframe; a separate pretest result or an analysis of change from baseline is not reported in the registry record.

The registry record gives a start date of 2022-09-27, a primary completion date of 2023-12-23, and a completed status. The phase is listed as NA. Additional details on allocation procedures, concealment, classroom clustering in the analysis, and protocol deviations are not reported in the registry record. Those details can affect how a randomized classroom study is interpreted, so the reported design labels alone should not be taken as evidence that every aspect of implementation or analysis is known.

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: Teachers were potential participants who were screened for the purpose of determining eligibility, but who did not participate and thus were not considered enrolled, due to the low frequency of potential participants (N = 51). Teachers whose students were in the intervention group were compensated for giving up instructional time to the intervention and for helping facilitate delivery of the program.

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 School Belonging Scale, measured over one week following completion of the 8-week intervention.

The primary endpoint is the School Belonging Scale, an eight-item student self-report measure intended to represent perceived school belonging. Each item uses a rating scale ranging from 1 (really not true) to 6 (really true). The average across the items forms the final score, with higher scores indicating higher perceived school belonging. The reported unit is a score on a scale, and the primary summary statistic is the mean.

Belonging is relevant to a study focused on peer relationships and inclusive classroom experiences because it captures how children perceive their membership in the school community. It is distinct from direct measures of prejudice, intergroup friendship, or teacher attitudes. Consequently, the primary result answers a question about reported belonging, not all dimensions that the program sought to influence.

The registry description notes that the measure was shortened from the original Psychological Sense of School Membership scale and gives reliability information for the original measure and pilot testing of the shorter version. The shorter version’s reported internal reliability in pilot testing was 0.714. The description also says that construct validity was indicated through a significant relationship with teacher ratings of student social standing. These details explain the intended measurement basis, but they do not establish how consistently the measure performed in the trial sample. Trial-specific measurement reliability is not reported in the registry record.

The primary timeframe is one week following completion of the eight-week intervention. This specifies when the outcome was assessed; it does not establish whether any difference persisted beyond that assessment. Longer-term follow-up results are not reported in the registry record.

7. Results Posted in the Registry

• Intervention: DIY Tool Classrooms: mean 4.72 versus 4.72 on control; difference 0.00 (95% CI -0.22 to 0.22), standardized effect d = 0.00; z-test p = 1.000.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous: each child’s scale score is a numeric quantity, and the registry reports the mean for each arm. A mean provides a concise description of the center of a group’s scores. It does not show the full range, shape, or clustering of individual responses. For this reason, the mean is usually interpreted alongside a measure of uncertainty and, when available, measures of variability or a distributional display.

For DIY Tool Classrooms, the reported mean is 4.72 with a standard error of 0.07. For Business As Usual Classrooms, the reported mean is 4.72 with a standard error of 0.09. The comparison is expressed as the intervention mean minus the control mean, with a reported estimate of 0.0. The registry also reports a standardized effect size of 0.0. A standardized effect expresses a group contrast in units of a measure of score variability; it is useful for putting effects measured on different scales into a common framework, but the value remains tied to the specific comparison and assumptions used.

The record gives a pooled standard deviation of 1.648. In general, a standard deviation describes how scores vary around their mean. A pooled standard deviation combines information about variation in the groups for a comparison, according to a particular calculation. The registry identifies the reported effect as an unadjusted comparison. The record does not give enough detail to infer every computational choice behind that comparison, so the estimate should be described as posted rather than as a reconstruction of an undocumented analysis.

The standard error is different from the standard deviation. In general, standard error describes uncertainty in an estimated quantity, such as a group mean, rather than the variation among individual scores. It depends on the variability of observations and the amount of information contributing to the estimate. The values 0.07 and 0.09 are the reported standard errors for the arm means. They should not be read as the typical distance between individual children’s scores and their group mean.

The comparison also includes a confidence interval. In general, a confidence interval gives a range of values compatible with the data and the statistical procedure used, subject to its assumptions. A narrow interval indicates greater precision than a wide interval on the same scale. The registry’s reported interval for the mean difference includes zero, so the data are compatible with no mean difference as well as with values on either side of zero within the interval. The interval is not a guarantee that the true effect lies within its limits, and it does not directly state the probability that a particular effect is true.

The unadjusted p-value is 1.0. In general, a p-value assesses how unusual the observed data, or data more extreme, would be under a specified null model. It does not measure the probability that the null hypothesis is true, the probability that the result arose by chance, or the importance of the effect. The p-value must be interpreted with the effect estimate, interval, design, and analysis details. In this result, the estimate itself is 0.0, so the p-value is not a separate measure of how much the groups differ.

The registry describes the trial as randomized, parallel, and unmasked. Randomization is intended to make the assigned groups comparable in expectation, while a parallel design compares separate groups over the study period. In general, randomization does not prevent all imbalances, losses to follow-up, or implementation differences. Unmasked status also means that participants or study staff could have known the assigned condition, although the record does not specify which people knew assignments or whether outcome assessment could be influenced by that knowledge.

Because the intervention is delivered in classrooms, an important general consideration is whether outcomes from children in the same classroom are correlated. Children sharing a teacher and setting may have more similar outcomes than children in different classrooms. If a study’s analysis does not account for such clustering when it is present, uncertainty estimates can be affected. The analysis details needed to determine how clustering was handled are not reported in the registry record. This is a methodological question, not evidence that the posted estimates are incorrect.

Over-dispersion is a general issue in statistical modeling when observed variation is greater than a model assumes. If present, it can make model-based uncertainty estimates too small unless the analysis accounts for it. The endpoint is a continuous scale score, and the registry does not report a model specification or a diagnostic assessment for over-dispersion. It is therefore not possible to say whether this issue applied to the reported analysis; the concept is relevant only as a general reminder to match model assumptions to the data.

The registry also describes planning illustrations based on the observed effect, using a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. Such illustrations concern hypothetical planning under stated assumptions. They are not observed power, and they are not the trial’s own sample-size justification. The registry record does not report the trial’s sample-size justification or a detailed statistical analysis plan. The posted result, rather than a planning illustration, is the basis for interpreting the observed comparison.

10. Confidence Intervals and Precision

The point estimate for the primary comparison is a mean difference of 0.0. The posted confidence interval extends from a negative value to a positive value and therefore includes zero. Its position is consistent with the equal reported arm means of 4.72. The registry also reports standard errors of 0.07 in the DIY arm and 0.09 in the business-as-usual arm. These values describe uncertainty around the arm means, while the confidence interval describes uncertainty around the difference between them.

In general, precision is about how tightly the data estimate a quantity. A point estimate alone does not show precision: an estimate can be near zero with either a relatively narrow or a wide interval. The interval matters because it indicates which contrasts remain compatible with the observed data under the method used. Since the reported interval crosses zero, the result does not distinguish a zero mean difference from values on either side of zero within its bounds.

The confidence interval should not be treated as a range of individual children’s scores. It concerns the group-level mean difference. Nor does it address every form of uncertainty: it does not, by itself, account for unreported design or analysis details, measurement error, missing outcomes, or the possibility that the endpoint does not represent all relevant dimensions of inclusion.

The displayed interval is a recalculated, unadjusted comparison from posted summary statistics, and the registry does not flag a discrepancy between that comparison and the sponsor’s analysis. A recalculated interval is informative as a transparent summary-statistic comparison, but it is not a substitute for a fully documented trial analysis. The sponsor’s own analysis takes precedence if a discrepancy is reported; no such discrepancy is recorded for this result.

Precision is also outcome- and time-specific. This interval concerns the School Belonging Scale at one week following completion of the intervention. It does not establish precision for unposted secondary outcomes, subgroup contrasts, or longer-term results. Those estimates are not reported in the registry record.

11. Multiplicity, Missing Data and Analysis Populations

The record lists 12 outcome measures but posts no secondary results. It reports the School Belonging Scale as the primary outcome. When a study evaluates multiple outcomes or multiple subgroup contrasts, general statistical practice considers multiplicity: the more comparisons examined, the greater the opportunity for some results to appear noteworthy by chance. Whether and how to address this depends on the prespecified analysis plan and the role of each outcome. Adjustment procedures, outcome hierarchy, and any multiplicity strategy are not reported in the registry record.

The registry reports an unadjusted p-value of 1.0 for the primary comparison. It does not report an adjusted p-value or describe a family of tests for which adjustment was applied. The result should therefore be described using the posted unadjusted comparison, without assuming a correction or a prespecified testing sequence. The absence of posted secondary results also means the broader study aims cannot be evaluated from the primary result alone.

Missing data are a separate concern from multiplicity. The record reports arm counts of 522 and 363, but does not explain whether every enrolled participant contributed a primary outcome, how missing scores were handled, or whether any imputation or sensitivity analysis was used. The stated arm counts should not automatically be interpreted as the number of complete outcome observations. Reasons for missing data and follow-up rates are not reported in the registry record.

The analysis population is also not described in sufficient detail to identify whether the primary analysis included all randomized participants, only participants with observed posttest data, or another population. The registry record does not report an intention-to-treat designation, a per-protocol analysis, or exclusions after randomization. These are important distinctions because the analyzed population can affect how a randomized comparison is interpreted.

The record does not report an interim analysis plan, a stopping rule, or the trial’s detailed statistical analysis plan. These omissions do not establish that such procedures were absent; they mean that they cannot be characterized from the registry record. A complete interpretation of missing data, analysis populations, and multiplicity would require those details.

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 no serious adverse events among participants at risk in either group: 0 of 522 in the DIY Tool Classrooms and 0 of 363 in the Business As Usual Classrooms. It also reports no other adverse events in either group and 0 deaths in each group. No serious adverse event terms are listed.

These figures describe the events recorded in the registry for the reported groups. A zero count means that no events of the specified category were reported as affecting participants in that group during the reporting period; it does not prove that no event occurred outside the information captured, or that an intervention has no possible risk. The record does not provide further information about event definitions, the duration of safety surveillance, or how events were assessed for relationship to the intervention.

The figures should also be read separately from the primary effectiveness result. They do not explain the School Belonging Scale comparison, and the primary outcome does not measure safety. No causal conclusion about safety can be drawn from the event counts alone. The counts are a description of reported serious and other events and deaths in the registry record, not a complete safety assessment.

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

The posted primary result shows equal reported mean School Belonging Scale scores of 4.72 in the intervention and control arms. The reported mean difference is 0.0, and the unadjusted p-value is 1.0. The confidence interval includes zero. These summaries describe the observed primary comparison at the stated assessment time and do not show an estimated separation between the arm means.

That result does not demonstrate that the DIY program changed school belonging, nor does it prove that the program has no effect. A statistical estimate is specific to the participants, measure, timing, and analysis represented in the record. The result cannot establish what might have been observed at another time, in another population, with another measure, or under a different implementation.

The trial summary names several broader questions, including prejudice, bias, intergroup friendships, subgroup differences, and teacher attitudes. The posted primary result does not answer those questions. Secondary results are not posted in the registry record, so no conclusions about those outcomes or the listed subgroup comparisons can be drawn from these data.

The endpoint itself has a specific interpretation: higher scores indicate higher perceived school belonging on an eight-item self-report scale. It is not a direct measure of friendship formation or prejudice, and it does not capture every aspect of classroom inclusion. A mean score also does not describe each child’s response. The registry does not provide the score distribution, individual-level patterns, or trial-specific measurement reliability.

The result should therefore be understood as a bounded statistical finding rather than a general verdict on the intervention. It is a comparison of the reported average belonging scores one week after an eight-week program, with no difference in the posted means. Questions about the precision and validity of other outcomes, the durability of any changes, missing outcome data, and how the analysis handled classroom structure remain unresolved in the registry record.

14. Why This Trial Matters Statistically

This trial is statistically informative because its primary question is framed around a measurable student-reported outcome in a randomized, parallel-group comparison. Reporting the arm means, standard errors, mean difference, standardized effect, confidence interval, and p-value allows readers to distinguish the estimated effect from the uncertainty around it. In particular, the equal reported means and mean difference of 0.0 make clear that the primary posted estimate does not show a difference in average school belonging.

The study also illustrates why the endpoint matters. The trial’s broad purpose includes peer relationships and prejudice, while the posted primary measure captures perceived school belonging. Those constructs are related to the study’s context but are not interchangeable. A conclusion about the primary measure cannot stand in for results on the other intended outcomes, which are not posted in the registry record.

The classroom setting raises design and analysis questions that are important in education and behavioral research. Children may share classroom experiences, so the unit of assignment and the handling of within-classroom similarity can affect statistical uncertainty. The registry identifies the design as randomized and parallel, but does not report enough detail to evaluate the analysis of classroom grouping. Recognizing that limitation is part of assessing how much can be learned from a result.

Finally, the record separates an observed result from planning illustrations. Planning calculations based on an observed effect do not represent the trial’s observed power or its original sample-size justification. This distinction matters because sample-size planning, estimation, and interpretation answer different statistical questions. The strongest supported conclusion remains focused on the posted primary score and its uncertainty, while broader claims require results and methods that are not reported in the registry record.

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 registry record gives limited detail about the implementation and analysis. It does not specify the precise unit of randomization, allocation concealment, or how classroom-level clustering was handled. Since the program was delivered in classrooms, those details matter for interpreting standard errors and confidence intervals. Their absence from the record is a reporting limitation, not evidence that the study did or did not account for them.

The arm counts are reported, but the number of participants with observed primary endpoint data is not separately stated. The record does not describe missing scores, attrition, exclusions, or the analysis population. As a result, it is not possible to determine from the registry whether all enrolled participants contributed to the reported comparison or how missing outcomes might affect it.

The outcome is a shortened self-report measure assessed one week after the intervention. The registry gives reliability information from pilot testing and describes construct validity evidence, but does not report reliability in the trial sample. Self-report can capture children’s own perceptions, but a score does not provide a complete account of peer relationships or classroom inclusion. The record does not report follow-up beyond the stated timeframe.

The trial summary describes a broad set of aims, including prejudice, intergroup friendships, subgroup differences, and teacher attitudes. The registry lists 12 outcome measures but posts no secondary results. Consequently, the primary result cannot establish effects on these other questions. Analysis details, multiplicity procedures, subgroup methods, and a detailed statistical plan are not reported in the registry record.

The study is listed as unmasked. The registry does not say who knew the group assignments or how expectations may have affected delivery, classroom discussion, or self-reported scores. It also does not provide enough detail to assess variation in implementation across classrooms. These limitations restrict interpretation of the posted result but do not change the descriptive fact that the reported arm means were both 4.72.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Developing Inclusive Youth: Promoting Intergroup Friendships and Inclusive Classrooms in Childhood — NCT05619523.
• Registry record last updated 2025-09-02; status last verified 2025-08.
• Results first posted 2025-09-02.
• 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 completed randomized, parallel-group trial compared Developing Inclusive Youth Tool Classrooms with Business As Usual Classrooms. The registry reports 885 enrolled participants and lists 522 in the intervention arm and 363 in the control arm. The intervention used an online curriculum with teacher-led discussion and was described as occurring once a week for eight weeks.

The primary outcome was the mean School Belonging Scale score one week after intervention completion. Both arms had a reported mean of 4.72. The posted mean difference was 0.0, with an unadjusted p-value of 1.0; the confidence interval includes zero. No serious adverse events, other adverse events, or deaths were reported in either group.

The registry record does not post secondary results or sufficient detail to assess missing data, analysis populations, classroom clustering, multiplicity procedures, or the full statistical plan. The primary result therefore addresses the reported school-belonging comparison only and should not be extended to the trial’s broader questions.