Behavioral Economics for Activity Motivation in Adolescents (BEAM): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Behavioral Economics for Activity Motivation in Adolescents (BEAM) (NCT04874415), a randomized na study. The primary outcome is Change in Moderate to Vigorous Physical Activity (MVPA).

2. Clinical Question

3. Trial Design

The registry identifies BEAM as a randomized, single-masked, factorial behavioral trial. Its enrollment is listed as 75. The record lists the trial status as completed, with a start date of 2021-11-16 and a primary completion date of 2024-10-04. Phase is recorded as not applicable.

The intervention descriptions vary along several dimensions. Some conditions use one text per day and others use two texts per day. Goals are either ramped or fixed; incentives are framed as gains or losses; and goals are assessed over daily or weekly periods. The named conditions combine these features. The registry's arm descriptions include fixed-goal and ramped-goal variants, while the intervention list also names several behavioral conditions. The record does not explain how those arm descriptions map onto the trial's factorial factors or which contrasts were prespecified.

The brief summary describes a mobile health approach combining text messaging and financial incentives. The trial is presented as addressing physical activity among adolescents and young adults with type 2 diabetes and prediabetes. The conditions field additionally lists insulin resistance and polycystic ovary syndrome, but the record does not provide detailed enrollment criteria or explain how these conditions relate to the enrolled population.

Although randomization and factorial structure are recorded, the allocation method, masking procedures, allocation ratio, and specific analysis model are not reported in the registry record. The protocol's rationale for the enrollment target and any sample-size justification are also not reported. Consequently, the design can be described by its recorded features, but details needed to reconstruct its planned contrasts and analysis cannot be established 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: n=75 participants signed consent to participate in the study. n=74 completed the baseline study visit and 2-week run-in using Fitbit. Those with insufficient Fitbit data or more than 30 minutes of moderate-vigorous physical activity daily were excluded prior to randomization (n=7).

Only the first 6 of 16 groups are shown.

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.

Only the first 6 of 17 groups are shown.

6. Primary Endpoint

The registry lists the primary outcome as Change in Moderate to Vigorous Physical Activity (MVPA), measured over 12 weeks.

The primary endpoint is change in moderate-to-vigorous physical activity, abbreviated MVPA, measured in minutes per day. The registry describes it as the change from baseline in weekly mean minutes of MVPA per day, with a 12-week timeframe. The reported statistical quantity is a least-squares mean, accompanied by a 95% confidence interval.

In general, an activity measure can provide a behavioral outcome directly related to the intervention's stated aim of encouraging physical activity. The record identifies change rather than only an endpoint value, so the intended measure reflects movement from each participant's baseline level. A weekly mean also describes average daily activity over a week rather than one isolated day's activity. The registry does not explain how activity was measured, how MVPA was defined operationally, or how weekly averages were calculated.

A least-squares mean is generally a model-based mean that can account for terms included in a statistical model. The registry record does not report the model specification, so it is not possible to determine which covariates, repeated-measure terms, or factorial effects informed the estimate. A 95% confidence interval expresses uncertainty around an estimate under the assumptions of the analysis; it does not by itself show whether an effect is important to participants. The numerical endpoint estimates and confidence intervals are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a least-squares mean represent?

The primary endpoint is specified as a least-squares mean. In general, this is a mean estimated from a statistical model rather than a simple arithmetic average of all observed values. A model may adjust for covariates or account for features such as repeated measurements, but what it adjusts for depends on the model specification. The registry record does not report that specification, so the precise interpretation of the registered least-squares mean cannot be reconstructed.

For a change outcome, the quantity of interest is the modeled change in weekly mean daily MVPA from baseline over the stated 12-week timeframe. A contrast between conditions would ordinarily compare estimated changes or compare changes against a reference. The registry record does not give a single primary contrast or report the estimates, so no particular contrast can be described as the trial's reported effect.

How should a 95% confidence interval be read?

In general, a confidence interval conveys uncertainty around an estimate. Its width reflects statistical precision under the assumptions used to calculate it; it is not a guarantee that the true value lies inside a particular interval. A confidence interval should be interpreted together with the estimate, the outcome's units, the comparison being made, and the analysis method. The endpoint is expressed in minutes per day, but the primary estimates and intervals are not reported in the registry record.

A confidence interval also does not determine whether a difference matters in practical terms. That judgment requires context about meaningful changes in the outcome, which is not reported in the registry record. The record's designation of a 95% interval tells the reader the stated interval level, but not whether a clinically meaningful threshold was defined.

What does factorial design allow?

In general, factorial designs vary multiple intervention components so that their effects can potentially be evaluated within one trial. In this trial's descriptions, those components include the number of texts per day, fixed or ramped goals, gain or loss incentives, and daily or weekly goal periods. A factorial analysis might estimate an average effect for one component across levels of other components, or evaluate whether components work differently in combination. The registry record does not report which factorial effects or interactions were included in the planned primary analysis.

Because the registry lists multiple named conditions, it is important not to assume that a result from one condition would answer the same question as an average effect across a factor. The intended reference condition, pooling strategy, and factor coding are not reported in the registry record. The record also does not explain the relationship between all arm descriptions and the intervention names.

What can be inferred from the analysis labels?

The primary outcome is described using least-squares means and 95% confidence intervals. Those labels identify the type of summary intended, but do not disclose the model, adjustment variables, handling of repeated observations, or method for calculating uncertainty. The statistical analysis plan is not reported in the registry record. Thus, readers should distinguish the stated endpoint and summary measure from the unreported model details.

The registry records 10 outcome measures and 40 analyses, alongside the named primary and secondary outcomes. Multiple outcomes and analyses can create multiple opportunities to observe apparently notable findings. In general, multiplicity procedures can control the interpretation of a family of statistical tests, but whether any such procedure was planned or used is not reported in the registry record. No p-values or primary estimates are available in the registered information described for this trial, so this record does not permit a reanalysis or assessment of statistical significance.

How do planning illustrations differ from power?

In general, a sample-size calculation can illustrate the number of participants per arm that would be needed under stated assumptions to detect a chosen effect at a chosen significance level and power. The assumptions recorded for the planning illustration use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is expressed as a fraction of the observed effect. Such illustrations are planning calculations, not observed power and not evidence that the trial had adequate power for its actual analysis.

The registry record does not report the sample-size justification used to design the trial or the numerical planning illustrations. It also does not report the observed primary effect needed to interpret an illustration based on that effect. The planning assumptions therefore should not be treated as a description of the trial's actual allocation or as a substitute for its results.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists several secondary outcomes, including daily step count, BMI z-score, plasma glucose, insulin, hemoglobin A1c, triglycerides, LDL, and HDL. It also records 10 outcome measures and 40 analyses. The primary outcome is noted as having several categories or time points, and it was not reduced to one comparison. These features make it important to know how the investigators distinguished primary, secondary, and exploratory findings.

In general, when many outcomes, time points, or comparisons are analyzed, the chance of a nominally notable result can increase unless the analysis accounts for multiplicity or interpretation is otherwise carefully qualified. Whether the trial used a multiplicity adjustment, a hierarchy of tests, or another strategy is not reported in the registry record. The prespecified analysis plan and the rationale for the number of analyses are also not reported.

The registry record does not report how missing outcome observations were handled, whether imputation was used, or how participants with incomplete follow-up were included in the analyses. The analysis populations, including whether analyses followed intention-to-treat principles, are not reported in the registry record. These omissions matter because missingness and analysis-population choices can affect estimates and their uncertainty.

The factorial structure also makes the planned comparisons relevant to interpretation. The record does not describe whether the analysis emphasized main effects, interactions, specific condition-to-condition comparisons, or some other contrast. Without those details, the scope of any multiplicity strategy and the meaning of the 40 recorded analyses cannot be established.

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 5% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports serious adverse events and deaths for the listed condition groups. Serious adverse events are recorded as 0 in every listed group, and deaths are also recorded as 0 in every listed group. Other adverse events are recorded in several groups, while some groups have none. The group-specific counts and numbers at risk are reported separately in the registry.

These figures should be read as event counts within the listed groups, not as a comparison adjusted for differences in group size or follow-up. The numbers at risk vary among groups, and the registry record does not explain the adverse-event collection period or provide event descriptions beyond the recorded group information. It does not list top serious adverse-event terms.

In general, an observed count of zero serious events does not establish that no such event could occur, particularly when group sizes are limited. Likewise, counts of other adverse events do not by themselves show whether an intervention caused an event or whether risks differed between conditions. The registry's counts are descriptive safety information; they do not support a causal comparison without further definitions and analysis.

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

The registry record documents a randomized factorial behavioral trial aimed at promoting physical activity through text messaging and financial incentives. It defines change in MVPA as the primary endpoint and specifies a 12-week timeframe. This establishes the outcome the trial was intended to assess, but the registry record does not provide a single primary comparison or numerical results for that endpoint.

That absence means the registered information does not permit a quantitative statement about how much MVPA changed, how estimates differed among conditions, or how precise any difference was. It also does not support a conclusion that one messaging frequency, goal approach, incentive framing, or goal period was better than another. The trial's completed status is not itself evidence of a particular result.

The results should also be distinguished from the trial's rationale. The brief summary describes a need for interventions to address low physical activity among adolescents and young adults with diabetes or prediabetes. That motivation explains the research question; it does not establish what the intervention achieved. Similarly, a behavioral intervention's design does not guarantee that participants changed their activity.

The safety record lists no serious adverse events or deaths in the reported groups, and it records other adverse events in some groups. These counts are descriptive and do not, on their own, establish that an intervention caused or prevented an event, or that safety was equivalent across conditions.

In general, a trial result is best understood alongside its effect estimate, confidence interval, analysis population, missing-data approach, prespecified comparisons, and relevant context for practical importance. Several of those elements are not reported in the registry record. The appropriate reading is therefore limited: the record describes the trial design, endpoint, and some safety counts, but does not provide enough primary-outcome results to evaluate the size or precision of an activity effect.

13. Why This Trial Matters Statistically

This trial is statistically notable for its factorial intervention structure. The conditions combine variation in text frequency, goal-setting approach, incentive framing, and goal period. In general, factorial designs can use comparisons across combinations of components to estimate component effects efficiently, but the estimates depend on the contrasts and interactions specified in the analysis. The registry record does not report which factorial effects were intended to answer the primary question.

The endpoint is also a change measure rather than a single follow-up level: it concerns change from baseline in weekly mean minutes of MVPA per day over 12 weeks. Such a measure makes the baseline reference and the handling of repeated measurements relevant to interpretation. The registry identifies least-squares means and 95% confidence intervals, but does not report the model details needed to understand adjustment and uncertainty.

The registry records multiple outcomes and analyses. This makes transparent outcome prioritization and multiplicity handling important, especially when readers are considering results across activity, metabolic measures, and other endpoints. The record does not report whether or how multiplicity was addressed. Nor does it provide a single numerical primary result for interpretation.

Finally, an enrollment of 75 and multiple condition descriptions place emphasis on precision and on the choice of estimand. The registered information does not include a sample-size justification, analysis populations, or a primary contrast estimate. Those omissions limit what can be inferred from the record, regardless of the breadth of outcomes listed. The trial illustrates why an outcome definition and a design label are not enough on their own: the planned comparison, analysis details, and estimates with uncertainty are essential to assess what the data show.

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 registry record does not report detailed eligibility criteria, the age range, or how participants were distributed among the listed conditions. Although the official title and brief summary refer to adolescents and young adults with prediabetes or type 2 diabetes, other listed conditions include insulin resistance and polycystic ovary syndrome. The relationship between these condition labels and actual enrollment is not explained.

The intervention descriptions identify several factors, but the record does not fully clarify how all named conditions relate to the listed intervention arms or to the factorial analysis. The allocation method, allocation ratio, masking procedures, and details of the statistical model are not reported in the registry record. Nor is the precise primary contrast identified.

The primary outcome is described as change in weekly mean MVPA per day, but the activity-measurement method, operational definition of MVPA, and calculation of the weekly mean are not reported. The registry notes multiple categories or time points and does not reduce the primary outcome to one comparison. Numerical primary-outcome estimates and confidence intervals are not reported in the registry record.

Other limitations of interpretation include unreported sample-size justification, missing-data handling, analysis populations, and multiplicity methods. The registry lists secondary outcomes and numerous analyses, but does not provide enough analysis-plan detail to determine how findings should be prioritized. The adverse-event record provides group counts, but the collection period and event definitions are not described. These limitations concern the available registry information; they do not establish that the trial itself lacked methods or documentation beyond what is recorded.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Behavioral Economics for Activity Motivation in Adolescents (BEAM) — NCT04874415.
• Registry record last updated 2025-10-28; status last verified 2025-10.
• Results first posted 2025-10-09.
• 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 factorial behavioral trial sponsored by the University of Pittsburgh, with enrollment listed as 75. The trial evaluates mobile health strategies using text messages and behavioral economic-informed financial incentives to promote activity among adolescents and young adults with prediabetes or type 2 diabetes.

The primary endpoint is change from baseline in weekly mean minutes of MVPA per day over 12 weeks, summarized as a least-squares mean with a 95% confidence interval. The registry notes that the primary outcome has multiple categories or time points and is not reduced to one comparison. Numerical primary results are not reported in the registry record. Serious adverse events and deaths are recorded as 0 in each listed group; other adverse events are reported by group.

The registry does not report the primary analysis details, multiplicity approach, missing-data handling, or analysis populations. Consequently, the record supports a description of the trial's design and registered outcome, but not a quantitative conclusion about the primary activity effect.