Mindfulness-Based Resilience Training for Aggression, Health, and Stress Among Law Enforcement Officers: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Mindfulness-Based Resilience Training for Aggression, Health, and Stress Among Law Enforcement Officers (NCT03784846), a randomized na study. The primary outcome is Change in Aggression.

2. Clinical Question

The study’s stated purpose was to identify, optimize, and refine clinical and research practices across two sites in preparation for a future multisite efficacy trial. Its focus was therefore not limited to a single comparison of aggression: the registry also lists biological, behavioral, and psychological outcomes. Secondary outcomes include changes in inflammatory markers, psychological resilience, alcohol use and its negative consequences, and depression.

The trial record identifies random allocation and a parallel-group model. It lists MBRT and SME as behavioral interventions and also describes a no-intervention control. The clinical question can be framed as whether aggression scores changed over time in the groups assigned to these different conditions. However, the registry record does not report the numerical changes, between-group contrasts, confidence intervals, or test results needed to assess the direction, size, or precision of any group difference.

3. Trial Design

The registry record describes a randomized, single-masked, parallel-group study with enrollment of 109. The study status is completed. Its phase is listed as not applicable. The record identifies Pacific University as the sponsor and gives the study start as 2019-10-01 and primary completion as 2022-05-17.

Three conditions are named in the record: Mindfulness-Based Resilience Training, Stress Management Education, and a no-intervention control. MBRT is described as an 8-week program combining standardized mindfulness practices, cognitive behavioral therapy, and psychoeducation. SME was designed as an active control for mindfulness-based intervention trials. Its group-based, didactic modules addressed physiological and dietary effects of stress, time management, sleep physiology and insomnia, nutrition, exercise, stress hardiness, and factors mitigating stress. The no-contact control involved no contact other than baseline, post, and follow-up assessments.

The primary outcome was change in aggression. Measurements were specified at baseline, post-intervention (week 8), 3-month followup, and 6-month followup. The record states that participant counts at post-intervention and follow-up reflect attrition or participants lost to followup. It does not report the number assigned to each condition at randomization, the randomization procedure, the identity of the masked party, or whether masking was maintained throughout the study.

The study summary describes work to refine practices across two sites for a future multisite efficacy trial. The registry record does not report details of site-level recruitment, allocation procedures, or how the study’s preparatory aims were assessed. Although it lists a range of secondary outcomes, it does not report a statistical analysis plan or numerical primary-outcome results. These gaps limit what can be concluded about the conduct and findings of the trial from the registry record alone.

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: All enrolled participants were assigned to a study arm.

Pre-COVID Study

Reasons for not completing this period:

Post-COVID Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Numbers at post-intervention, 3-month followup, and 6-month followup reflect attrition or participants or lost to followup.

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 Change in Aggression, measured over baseline, post-intervention (week 8), 3-month followup, 6-month followup.

The primary endpoint is change in aggression measured with the Buss-Perry Aggression Questionnaire-Short Form. The registry describes the measure as a score on a scale ranging from 1-5, with higher scores indicating greater aggression. The endpoint is recorded as a mean with standard deviation, and the specified assessments are baseline, post-intervention (week 8), 3-month followup, and 6-month followup.

As a general statistical point, a repeated measure can describe whether scores change over time within a group and whether those changes differ between groups. The latter comparison is important in a randomized trial: change in one group alone does not establish that its course differed from the course in a comparison group. A mean describes the group’s average score, while a standard deviation describes how spread out individual scores are around that mean.

Aggression was selected as the primary outcome in a study whose stated concerns include aggression and excessive use of force, as well as psychological health. The endpoint therefore addresses a central behavioral outcome in the study’s stated aims. The registry record does not report the actual means, standard deviations, changes, or between-group estimates. It also does not identify a single time point as the sole primary comparison, so the sequence of assessments should not be reduced to an unreported single result.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies a randomized, single-masked, parallel-group design. Random allocation is intended, in general, to make assigned groups comparable on average at the start of a trial. The parallel-group structure means participants are assigned to a condition and compared across conditions rather than each participant receiving every condition. The record does not describe the allocation sequence, concealment procedures, or who was masked, so those features cannot be assessed from the registry record.

What does a mean and standard deviation describe?

The primary outcome is continuous: a Buss-Perry Aggression Questionnaire-Short Form score summarized by a mean and standard deviation. In general, the mean is the arithmetic average of the measured scores in a group. The standard deviation describes how dispersed those scores are around the mean. A mean alone does not show whether most participants had similar scores or whether individual scores varied substantially; the standard deviation helps describe that variation.

The scale ranges from 1-5, and higher scores indicate greater aggression. This direction makes the score interpretable, but it does not supply a result. To describe change, the means at the scheduled assessments or an estimated change from baseline would be needed. To compare conditions, an estimate contrasting those changes would also be needed. The registry record does not report these numerical results.

Why does the timing of the endpoint matter?

The primary outcome was assessed at baseline, post-intervention (week 8), 3-month followup, and 6-month followup. In general, repeated measurements allow investigators to examine how an outcome develops over time. An analysis could focus on a particular follow-up, compare changes across follow-ups, or model the pattern across all assessments. These approaches answer different questions and can yield different estimates. The registry record does not report which approach was used, or a single primary time-point contrast.

Measurements from the same participant are generally related rather than independent. General methods for repeated data account for that relationship when estimating uncertainty. The registry record does not name a model, test, covariance structure, or other method used for the primary outcome. It is therefore not possible to determine how within-participant dependence or baseline measurements were handled.

What can a confidence interval tell readers?

In general, a confidence interval describes the uncertainty around an estimated quantity under the assumptions of the analysis. A narrow interval indicates greater statistical precision than a wide interval, while the interval’s location indicates which values are compatible with the estimate and method. A confidence interval does not by itself establish clinical importance, and it cannot correct for bias from missing data or an unsuitable analysis. No primary-outcome confidence interval is reported in the registry record.

A p-value, in general, measures how surprising data at least as extreme as those observed would be under a specified null model and its assumptions. It does not measure the size or importance of an effect. No primary-outcome p-value is reported. The registry record also does not report the statistical test or model, so there is no basis for interpreting an unreported test result.

How should the planning illustrations be read?

The sample-size illustrations are planning exercises based on the observed effect, not the trial’s own design justification. The stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. In general, such illustrations show how a hypothetical future study’s required enrollment can depend on the effect size selected and the chosen design assumptions. They are not observed power and do not show the probability that this completed study detected an effect.

The registry record does not report the trial’s own sample-size justification. The planning assumptions therefore should not be taken as evidence that the original enrollment was chosen using those assumptions. Nor do they establish that the trial was adequately powered for its primary endpoint or its secondary outcomes. Those conclusions would require the protocol’s rationale and the relevant outcome and analysis information.

Why does over-dispersion matter in general?

For outcomes analyzed as counts, over-dispersion means that the observed variation is greater than a chosen model expects. If a model assumes less variation than is present, its standard errors can be too small and its confidence intervals too narrow. This is a general concept, not a description of the primary aggression endpoint, which is recorded as a continuous score. The registry record does not identify an over-dispersion issue or a model for any secondary outcome.

More broadly, the registry names 22 outcome measures but does not report the analysis plan, the statistical methods used, or numerical estimates for the primary outcome. As a result, the design can be described, and general statistical principles can clarify what the measures would mean, but the posted record does not support a reconstruction of the trial’s inferential analysis.

10. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when analyses address several outcomes, time points, or group comparisons. In general, the more questions examined, the greater the chance that at least one result will appear noteworthy by chance if each is assessed without a plan for handling multiple tests. A prespecified hierarchy or adjustment can help define how evidence across multiple analyses is interpreted. The registry record lists 22 outcome measures and multiple primary-outcome assessment times, but it does not report a multiplicity strategy, outcome hierarchy, or statistical analysis plan. It is not possible to determine whether any adjustment was planned or used.

The record does not report the numerical primary-outcome results or the analyses performed; it lists zero analyses. Consequently, there is no basis for determining which comparisons were tested, whether analyses were selected after looking at the data, or how any multiplicity was addressed. These details are not reported in the registry record.

Missing data are also relevant. The primary-outcome description states that participant counts at post-intervention and follow-up reflect attrition or participants lost to followup. The registry record does not report the number of missing scores at each assessment, reasons for missingness, or whether loss to followup differed across conditions. It does not describe an imputation method, a sensitivity analysis, or assumptions about the missing outcomes.

The analysis population is not reported in the registry record. It is therefore unclear whether the analysis included all randomized participants, only those with available measurements, or another defined group. In general, the analysis population and missing-data approach affect the interpretation of a randomized comparison. Without those details and the numerical estimates, the extent to which attrition may have influenced the reported results cannot be assessed.

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 non-serious adverse event terms

The registry lists serious adverse events, other adverse events, and deaths for each condition. For MBRT, 50 participants were at risk for serious adverse events and 0 were affected; 50 were at risk for other adverse events and 1 was affected; deaths were 0. For SME, 38 were at risk for serious adverse events and 0 were affected; 38 were at risk for other adverse events and 0 were affected; deaths were 0. For the no-intervention control, 21 were at risk for serious adverse events and 0 were affected; 21 were at risk for other adverse events and 0 were affected; deaths were 0.

These are counts within the groups, not evidence by themselves that a condition caused or prevented an event. The registry lists no serious adverse event terms, and the one other adverse event in the MBRT group is not described. The record does not provide event timing, severity details for that event, exposure duration, or a statistical comparison. The figures should therefore be read as the adverse-event counts reported in the registry, with limited detail for assessing differences between conditions.

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

The registry record describes a randomized study of MBRT, SME, and a no-contact control among law enforcement officers, with change in aggression as the primary outcome. It also identifies a set of biological and psychological secondary outcomes. These details establish what the study was designed to examine, but the primary outcome’s numerical results are not reported in the registry record.

Without the group means, changes, between-group estimates, or confidence intervals, it is not possible to state whether aggression scores increased or decreased, whether changes differed across conditions, or how precisely any difference was estimated. The intervention descriptions and study design do not substitute for outcome results. No conclusion about the effect of MBRT or SME on aggression can be drawn from the design information alone.

The study summary frames the work as an effort to refine clinical and research practices for a future multisite efficacy trial. That preparatory aim is distinct from establishing an efficacy result. The registry record does not report enough information to assess how successfully the study met that aim, nor does it report a statistical analysis plan, analysis population, or missing-data approach.

The safety counts are also limited in meaning. No serious adverse events or deaths are listed for the conditions, and one other adverse event is listed for MBRT. These figures do not establish that an intervention is safe or unsafe, or that the conditions differ in safety. The registry record’s sparse event detail and lack of comparative analysis constrain interpretation.

In general, a trial result is best interpreted by considering the estimated effect, its precision, the analysis methods, missingness, and the outcome’s context together. The record reports the outcome framework but not the primary estimates or their uncertainty. It therefore supports a description of the trial and its intended questions, not a conclusion about treatment effects.

13. Why This Trial Matters Statistically

This trial is statistically relevant because it combines a randomized parallel design with a continuous behavioral outcome assessed at multiple follow-up times. Those features raise important questions about how change is defined, how repeated measurements are modeled, and which comparison is considered primary. The registry record specifies the measurement schedule but does not report the analysis used to translate those measurements into an estimate of group differences.

The study also names MBRT, an active education comparator, and a no-contact control. These conditions represent different comparison contexts. In general, comparing an intervention with an active control asks a different question from comparing it with a no-contact condition, because the active condition includes group-based educational content. The registry record identifies the conditions but does not report numerical contrasts that would show how the groups’ outcomes differed.

Multiple outcomes and follow-up assessments make transparent analysis planning important. The record lists 22 outcome measures, while the primary aggression measure has assessments at baseline and follow-up. Without a reported hierarchy, multiplicity approach, or analysis plan, readers cannot determine which comparisons were confirmatory or how uncertainty across the set of questions was handled.

Finally, the registry summary describes this work as preparation for a future multisite efficacy trial. That context makes clarity about feasibility, attrition, and measurement particularly relevant, yet the record does not provide detailed missing-data information or numerical outcome findings. The study’s statistical importance lies in its design and stated development purpose, while its publicly recorded results leave key inferential questions unanswered.

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.

A major limitation for interpretation is that numerical primary-outcome results are not reported in the registry record. The endpoint’s scale, direction, summary measure, and assessment schedule are described, but there are no means, standard deviations, changes, between-group estimates, or confidence intervals. The direction and magnitude of any observed aggression change therefore cannot be assessed.

The primary outcome has multiple assessment times, but the record does not specify which time point or longitudinal contrast was intended as the main comparison. It also does not report a statistical model, covariate adjustment, or a method for accounting for repeated observations. These omissions prevent readers from evaluating how the outcome schedule was translated into an analysis.

The record notes attrition or loss to followup but does not provide missingness counts by condition and assessment, reasons for loss, or a missing-data strategy. The analysis population is also not reported. These gaps matter because observed follow-up data may not represent all randomized participants in the same way across groups.

The registry lists 22 outcomes but does not report a multiplicity plan or analysis details. It is not possible to assess how the selection of outcomes and comparisons was handled. The masking description says single masked, but the identity of the masked party and the masking procedures are not reported. Allocation methods and the trial’s own sample-size justification are also not reported in the registry record.

Finally, the adverse-event information is limited to counts, with no serious event terms listed and no description of the one other adverse event recorded for MBRT. These limitations mean the registry supports a description of the study framework, but not a detailed assessment of its efficacy findings, robustness, or comparative safety.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Mindfulness-Based Resilience Training for Aggression, Health, and Stress Among Law Enforcement Officers — NCT03784846.
• Registry record last updated 2023-07-03; status last verified 2023-06.
• Results first posted 2023-07-03.
• 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.

18. Record Summary

The registry record describes NCT03784846, a randomized, single-masked, parallel-group study sponsored by Pacific University. It lists enrollment of 109, status as completed, and phase as not applicable. The study start was 2019-10-01, and primary completion was 2022-05-17.

The named conditions were Mindfulness-Based Resilience Training, Stress Management Education, and a no-intervention control. The primary outcome was change in aggression measured with the Buss-Perry Aggression Questionnaire-Short Form at baseline, post-intervention (week 8), 3-month followup, and 6-month followup. The registry also lists 22 outcome measures, including biological and psychological outcomes.

Numerical results for the primary endpoint, statistical analysis details, and an analysis population are not reported in the registry record. The record notes attrition or loss to followup in participant counts at post-intervention and follow-up. Its stated study purpose was to refine practices for a future multisite efficacy trial.