Effects of Mindfulness Training on the Psychological Well-being of Preschoolers: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effects of Mindfulness Training on the Psychological Well-being of Preschoolers (NCT05058365), a randomized na study. The primary outcome is Attention and Impulsivity.

2. Clinical Question

The trial asks whether a mindfulness course is associated with changes in preschoolers’ psychological well-being, with attention and impulsivity named as the primary outcome. The registry describes a randomized comparison between children assigned to the dots Curriculum and children assigned to a wait-list control condition. It does not report the outcome values or an analysis comparing the groups, so the record does not establish the direction or size of any difference.

3. Trial Design

The registry identifies this as a completed, randomized, parallel-group trial with single masking. It lists an enrollment of 18 and names the University of Hong Kong as sponsor. The recorded start date is 2021-09-01, and the primary completion date is 2022-06-30. The phase is listed as not applicable.

Participants were randomized to the dots Curriculum intervention or a wait-list control condition, according to the study summary. The wait-list group is described as receiving the same intervention two months after the experimental group completed it. The record does not provide further details about the randomization procedure, how the masking was implemented, or who was masked.

The summary describes several forms of assessment. Children were to complete a computerized task and an interview-based scenario test at baseline and after the intervention. Parents and class teachers were also invited to complete surveys at both time points. The primary outcome is attention and impulsivity, measured at baseline and immediately after intervention at Week 14. Although the trial is marked completed, completion status alone does not indicate whether outcome data were collected for every participant or what the results were. Those details are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

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 Attention and Impulsivity, measured over Baseline, Immediately after intervention at Week 14.

The primary endpoint is titled Attention and Impulsivity and is expressed in units on a scale. It is defined as the mean of eight measures from the Conners Kiddie Continuous Performance Test 2nd Edition (K-CPT 2): d-prime, Omissions, Commissions, Perseverations, Hit Reaction Time Standard Deviation, Variability, Hit Reaction Time Block Change, and Hit Reaction Time Inter-Stimulus Interval Change. Each measure is converted to a T-score, and the eight T-scores are averaged into an overall score. The registry states that lower scores indicate a better outcome.

In general, combining several measures into an aggregate can represent a broader construct than any single component, while also making the result dependent on how those components are defined and combined. Here, the registry describes an unweighted mean of the eight T-scores. The assessment is scheduled at baseline and immediately after intervention at Week 14, allowing change over time to be considered. However, the registry record does not report the observed endpoint values, variability, or a comparison between groups. It therefore does not show how the measure changed in this trial.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a randomized, single-masked, parallel-group design, but it does not report a statistical analysis for the primary endpoint. The explanations below are general statistical context, not a description of analyses confirmed to have been carried out in this trial.

What does randomization contribute?

In general, randomization assigns participants to groups by a chance-based process. Its purpose is to reduce the risk that group membership is systematically related to measured or unmeasured characteristics before treatment. It does not guarantee that groups will be identical, especially in a small study, and it cannot correct problems that arise after assignment, such as missing outcome measurements or differences in follow-up. The registry record does not report the sequence-generation or allocation-concealment procedures, so those features cannot be assessed from the record.

What does a mean and standard deviation describe?

The primary endpoint is a continuous aggregate score, and its specified summary parameter is the mean with standard deviation. In general, the mean describes the center of a set of numerical observations, while the standard deviation describes how spread out individual observations are around that mean. These summaries can be useful for continuous outcomes, but they do not show the distribution’s full shape. They also do not, by themselves, describe a difference between groups or a change from baseline. The registry record does not report means or standard deviations for the endpoint.

The endpoint is formed by averaging eight T-scores. The record states that the component scores use a population mean of 50 and a standard deviation of 10, and that lower values on the aggregate indicate a better outcome. In general, aggregation can simplify a set of related measurements into one score. Interpretation then depends on the chosen components, their scoring direction, and the rule used to combine them. No additional information about validation or reliability of this aggregate in the trial population is reported in the registry record.

How should a group comparison be interpreted?

In general, an analysis of a randomized trial may compare outcomes between assigned groups, compare changes from baseline, or use a model that accounts for baseline measurements. These approaches answer related but not identical questions and rely on different assumptions. The appropriate contrast depends on the trial’s analysis plan and the available data. The registry record does not report which approach was used, whether baseline adjustment was planned, or what model was fitted. It would therefore be inappropriate to assign a specific method to this study.

A point estimate describes the observed magnitude and direction of a difference or change. A confidence interval describes its statistical uncertainty under the model used. These are complementary: the estimate gives the central result, while the interval indicates how much uncertainty remains. Neither is reported for the primary endpoint. In general, uncertainty is especially important when a study has a small enrollment, because estimates can be imprecise and sensitive to the observations available. The enrollment figure alone does not quantify the endpoint’s precision.

What does the planning illustration mean?

The registry’s planning assumptions describe an illustration based on a stated fraction of the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. The record explicitly distinguishes this planning exercise from the trial’s own design. Such a calculation is not an observed trial result and is not observed power. It is a conditional illustration of sample size under stated assumptions. The actual effect estimate used for that exercise is not reported in the registry record, and the illustration should not be read as a record of the trial’s original sample-size justification. The trial’s own sample-size justification is not reported in the registry record.

In general, a sample-size calculation depends on assumptions about the effect to detect, outcome variability, error rates, allocation, and analysis method. If those assumptions differ from the actual study conditions, the calculated size may not describe the study’s achieved precision. No additional protocol assumptions should be inferred from the planning illustration. The registry record does not report interim analyses, stopping rules, or a detailed statistical analysis plan.

Why can over-dispersion matter?

In general, over-dispersion occurs when observed variation is greater than a statistical model assumes. It can make standard errors too small if the model does not account for that extra variation, leading to confidence intervals that are too narrow and test results that appear more decisive than warranted. This concept is most relevant to models for outcomes whose variability is tied to their mean, such as counts. The primary endpoint is described as a continuous mean score, and the record does not indicate that an over-dispersion model was used. No such analysis should be presumed.

10. Multiplicity, Missing Data and Analysis Populations

The trial lists 11 outcome measures, and the primary endpoint itself combines eight component measures. The registry record also notes that the primary outcome has several categories or time points and was not reduced to one comparison. When multiple outcomes, components, time points, or contrasts are examined, the chance of at least one apparently unusual result can increase if each is tested separately without a plan for handling multiplicity. In general, prespecifying a primary contrast or using an appropriate adjustment can help make interpretation more reliable. The record does not report a multiplicity strategy or identify a single numerical comparison for the primary endpoint.

The summary describes assessments at baseline and after intervention, including a computerized task, a scenario test, and parent and teacher surveys. The registry does not report how much outcome data were missing, how missing values were handled, or whether participants were analyzed according to their randomized group. It also does not report analysis populations, such as an intention-to-treat set or a per-protocol set. These omissions limit assessment of how representative any analysis might be, but no missing-data pattern or analysis choice can be inferred from the information recorded.

In general, missingness can affect interpretation when participants with unobserved outcomes differ from those whose outcomes are recorded. Methods for addressing missing data rely on assumptions, and those assumptions should be stated alongside the analysis. None are reported for this trial. The completed status does not establish that all planned observations were collected.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

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

The registry lists the intervention group and wait-list control group as having 9 participants at risk each. For both groups, the recorded number with serious adverse events is 0, the number with other adverse events is 0, and deaths are 0. No serious adverse event terms are listed.

These figures describe what is recorded in the registry, not proof that no adverse events occurred outside the recorded information. In general, a zero event count means that no events of that category were recorded among the listed participants at risk; it does not establish that an event is impossible or that the risk is absent. Interpretation also depends on how events were defined, collected, and followed over time. The registry record does not report further details about adverse-event definitions, surveillance procedures, or follow-up duration. The figures therefore should be read as a summary of the recorded safety data, not as a complete characterization of safety.

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

The record identifies a randomized comparison of the dots Curriculum with a wait-list control condition and defines attention and impulsivity as the primary endpoint. It also provides the endpoint’s construction, the direction considered better, and the intended assessment timing. These details make the research question and outcome operationalization understandable.

What the record does not provide is the information needed to answer the clinical research question from observed data. There is no reported primary-outcome estimate, group-specific summary, measure of uncertainty, or statistical test. The registry lists zero analyses, and notes that the primary outcome has several categories or time points and was not reduced to one comparison. As a result, the record does not show whether scores differed between groups, how they changed over time, or how precise any estimated difference might be.

In general, an outcome difference is not automatically equivalent to a meaningful change in well-being. Interpretation would depend on the magnitude and uncertainty of the estimate, the outcome’s measurement properties, the analysis population, and the clinical or developmental context. Those elements are not reported sufficiently to characterize a treatment effect in this record. No claim that the intervention works, does not work, or has a particular effect follows from the design description alone.

The adverse-event entries record no serious events, other events, or deaths in either group, among the participants listed at risk. Those entries are relevant descriptive information, but they do not replace a reported outcome analysis, and the record does not give the detail needed to assess event collection or completeness. Overall, the registry record documents a completed study framework and selected safety counts, while leaving the principal efficacy result and several analysis details unreported.

13. Why This Trial Matters Statistically

This trial is statistically notable because its primary measure is a constructed score rather than a single raw task result. The registry defines the score as the mean of eight K-CPT 2 T-scores. That approach can offer a compact summary of attention and impulsivity, but readers need the component definitions, scoring direction, and aggregation rule to understand what the summary represents. The record supplies the aggregation rule and states that lower scores indicate a better outcome.

The study also illustrates why a clear primary comparison matters. The endpoint is assessed at baseline and immediately after intervention at Week 14, while the record says the outcome has several categories or time points and was not reduced to one comparison. Without a stated contrast and an estimate, it is difficult to distinguish the main question from the many possible analyses that could be made from repeated measures and multiple outcomes. Reporting the chosen comparison and its uncertainty would be central to interpreting the trial statistically.

The enrollment of 18 makes careful attention to precision particularly important. In general, smaller studies can produce estimates with substantial uncertainty, and observed group differences may be sensitive to a small number of participants. The record does not report outcome variability or a confidence interval, so precision cannot be assessed. The planning illustration described by the registry is distinct from the trial’s own design justification and cannot substitute for a reported treatment-effect estimate.

Finally, the record distinguishes completion of the trial from completion of its statistical reporting. It provides design and endpoint details, but no analysis result. That distinction is useful for readers assessing what the registry can establish: it describes the planned scientific question, while the posted outcome evidence needed to answer it is not reported.

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 interpreting this trial from the registry record is the absence of reported primary outcome results. No means, standard deviations, group comparison, confidence interval, or inferential test is listed. The record also states that the primary outcome has several categories or time points and was not reduced to one comparison, leaving the target contrast unclear.

Information about participant characteristics, eligibility criteria, and the randomization procedure is not reported in the registry record. The masking field identifies the trial as single-masked, but the record does not say who was masked or how masking was maintained. These omissions prevent fuller assessment of the design and its implementation.

The registry summary describes assessments involving children, parents, and class teachers, but does not report completion rates or missing-data handling. It does not identify analysis populations, describe a detailed statistical plan, or state whether baseline adjustment or multiplicity control was used. It also does not report the trial’s own sample-size justification. These details affect how an eventual result could be interpreted, but should not be guessed.

The enrollment was 18, while the safety record lists 9 participants at risk in each group. The registry does not give further information about participant flow or explain whether all enrolled participants contributed data to each assessment. Therefore, the recorded at-risk counts should not be treated as a complete account of outcome availability. The zero adverse-event entries also lack additional detail about definitions and surveillance. These limitations apply to what can be concluded from the registry record, rather than establishing that the trial itself lacked the relevant procedures.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effects of Mindfulness Training on the Psychological Well-being of Preschoolers — NCT05058365.
• Registry record last updated 2024-09-19; status last verified 2024-04.
• Results first posted 2024-09-19.
• 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

NCT05058365 is a completed randomized, single-masked, parallel-group trial sponsored by the University of Hong Kong, with an enrollment of 18. It compares the dots Curriculum with a wait-list control condition; the wait-list group is described as receiving the intervention two months after the experimental group completed it.

The primary outcome is an aggregate attention and impulsivity T-score based on eight K-CPT 2 measures, assessed at baseline and immediately after intervention at Week 14. Lower scores indicate a better outcome. The registry lists 11 outcome measures and zero analyses, and does not report the primary outcome comparison or its uncertainty. The recorded serious adverse events, other adverse events, and deaths are 0 in each group, with 9 participants at risk per group.