Peer to Peer Delivery of Behavioral Activation: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Peer to Peer Delivery of Behavioral Activation (NCT02292849), a randomized na study. The primary outcome is Proportion of Peer to Peer Coaches Who Undergo Behavioral Activation Training and Achieve Certification.

2. Clinical Question

The study’s stated overall aim was to assess feasibility, acceptability and preliminary impact of peer-delivered Behavioral Activation for depressed older adults in the community settings described. That broad aim is not identical to the registered primary outcome: the primary outcome concerns coach training and certification, rather than a clinical measure in clients. Changes in Hamilton Depression Rating Scale Scores were listed as a secondary outcome.

The registry record does not report a primary-outcome result, an estimate of change in depression scores, or an analysis comparing the client groups. Consequently, the clinical question can be described from the study design, but the posted record does not provide results that establish the size or precision of any client outcome difference. The planned comparison also cannot, by itself, answer questions about settings or populations beyond those described in the record.

3. Trial Design

This was a randomized, parallel-group study with single masking, recorded as completed. The registry record lists an enrollment of 29 and the condition as depression. It records the phase as NA. The study started on 2013-11-01 and has a primary completion date of 2015-10-07.

Participants assigned to Peer to Peer were to receive a standard mental health referral to a community agency and, in addition, meet with a trained peer coach for 12 weekly meetings. Participants assigned to Referral were to receive the standard mental health referral to a community agency. The record does not state the allocation ratio, the method used to generate or conceal assignments, or which party was masked. The single-masking designation therefore does not identify who was unaware of group assignment.

The registered primary outcome is the count of eligible Peer to Peer coaches who underwent Behavioral Activation training and achieved certification. Its stated timeframe is 4 weeks prior to Baseline. The registry describes the outcome as a proportion but also lists its unit as participants and its parameter as a count. No result or denominator for this outcome is reported in the registry record.

Changes in Hamilton Depression Rating Scale Scores are listed as a secondary outcome. The registry lists 3 outcome measures, but gives no analyses for them. Although the study is randomized and has two client groups, the primary outcome is specific to Peer to Peer coaches; the registry record indicates that there were fewer than two arms for that primary outcome. No protocol details about the planned statistical methods, sample-size justification, or interim analyses are 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:

Analysis population for the primary outcome, as defined in the registry: This outcome analyzed Peer to Peer coaches who were eligible to provide the Behavioral Activation intervention

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 Proportion of Peer to Peer Coaches Who Undergo Behavioral Activation Training and Achieve Certification, measured over 4 weeks prior to Baseline.

The primary endpoint concerns Peer to Peer coaches eligible to provide the Behavioral Activation intervention. It asks how many underwent Behavioral Activation training and achieved certification. The stated measurement timeframe is 4 weeks prior to Baseline. The registry describes the endpoint as a proportion, while its unit and parameter describe a count of participants. The record does not supply a denominator or a result, so a proportion cannot be interpreted from the posted information.

Training and certification are process measures: they address whether coaches reached a specified preparation milestone before delivering the intervention. Such measures can be relevant to feasibility because implementation depends on having prepared coaches. They do not directly measure clients’ depression symptoms, acceptability, or the effect of the intervention on clients. The registry lists changes in Hamilton Depression Rating Scale Scores as a secondary outcome, but no result for that outcome is reported in the registry record.

The primary endpoint also differs in its unit of analysis from the randomized client comparison. It concerns eligible coaches in the intervention context, rather than a direct comparison of outcomes across the Peer to Peer and Referral groups. The registry record does not describe a comparison group of coaches or a statistical test for this endpoint. Its reported status as a count does not indicate how many eligible coaches were assessed or how many achieved certification. Without those details and the outcome result, the endpoint’s magnitude and precision cannot be evaluated.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry labels the primary outcome as a count of participants and classifies the outcome as binary. The outcome description asks whether eligible Peer to Peer coaches underwent Behavioral Activation training and achieved certification. In general, a binary outcome records whether a specified event or condition occurred for each eligible unit. A count then totals the units meeting that criterion. To interpret a count as a proportion, the number assessed must also be known. The registry record gives neither the reported count nor the eligible-coach denominator.

The record’s wording deserves care: it calls the outcome a “proportion,” while listing participants as the unit and a count as the parameter. Those terms describe related but distinct summaries. A count states how many participants met the criterion; a proportion places that count relative to an eligible group. Since no result or denominator is reported in the registry record, neither summary can be calculated or evaluated from the posted information. No recalculated result is available either.

Random allocation is a design feature intended, in general, to make treatment groups comparable on average, including on characteristics that were not measured. It does not guarantee that groups are identical, particularly in a small study. Here, the record says the trial was randomized and parallel, but does not report its allocation ratio or the method for generating or concealing assignments. The client groups are Peer to Peer and Referral. The listed primary outcome, however, concerns Peer to Peer coaches, and the record says there were fewer than two arms for that outcome. That explains why a two-arm treatment contrast is not available for the primary endpoint.

Single masking indicates that masking was recorded, but the record does not say who was masked. In general, masking can reduce the influence of expectations on some aspects of study conduct or outcome assessment, depending on who is unaware of assignment and how outcomes are measured. Without the masked party and assessment details, the practical implications of the designation cannot be determined in this case.

For a comparative clinical outcome, analysts commonly estimate the outcome in each group and then estimate a contrast between groups. The choice of contrast depends on the outcome and statistical plan. In general, uncertainty intervals help show which values are compatible with the data under the model, while a statistical test evaluates a specified null hypothesis. Neither a treatment contrast nor its uncertainty is reported for Hamilton Depression Rating Scale Scores. The registry also lists zero analyses, so no analysis result is available for interpreting a client-group contrast.

For binary outcomes, some analyses use a model for event counts or proportions. In general, the model must match the way the outcome was collected and account for the study design. If observations are more variable than a model assumes, over-dispersion can make standard errors too small and uncertainty appear narrower than it should. That is a general statistical concern, not a finding about this study: the record does not report a fitted model, dispersion estimate, or analysis of the primary endpoint.

The registry includes sample-size assumptions for planning illustrations: two-sided significance level 0.05, equal allocation between the two arms, and a normal approximation. It says that the effect to detect is a stated fraction of the observed effect, and distinguishes participant-per-arm illustrations from total-event illustrations for time-to-event outcomes. These are planning conventions, not the study’s reported design justification. No resulting sample-size values are present in the record, and no sample-size justification for the trial is reported there. Such illustrations must not be confused with observed power or with evidence that the study had a particular ability to detect an effect.

The registry does not report a statistical analysis plan, interim analyses, model specifications, covariate adjustment, handling of clustering, or procedures for multiple comparisons. The absence of these details means readers cannot establish which analytic choices were prespecified or how they would affect estimates. It would not be appropriate to infer a method from the trial’s randomization, its enrollment, or the names of its outcome measures.

The safety entries are also descriptive. In general, counts of participants with events and counts of events are not interchangeable: one participant may experience more than one event. The record gives entries labeled as participants at risk and participants affected, but does not give a statistical safety comparison or further detail on event handling. The reported group counts can be stated as recorded, but they do not alone establish a difference in safety between groups.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Peer to Peer Coaches")
n      <- c(11)
events <- c(7)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Peer to Peer Coaches  11  7  63.6  30.8  89.1  35.4  84.8  34.9  84.8

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 3 outcome measures and identifies changes in Hamilton Depression Rating Scale Scores as a secondary outcome. It does not describe a multiplicity procedure, a hierarchy among outcomes, or how the primary and secondary outcomes would be interpreted together. In general, when several outcomes are tested, the chance of at least one apparently unusual result can increase; a prespecified approach can help control or contextualize that issue. No such approach is reported in the registry record, and no outcome analyses are posted.

The primary endpoint is a coach training and certification count, whereas the secondary outcome concerns change in client depression scores. These address different aspects of the study and do not constitute interchangeable evidence. The registry does not give an analysis connecting coach certification to client outcomes. It also records zero analyses, so there are no posted test results, effect estimates, or confidence intervals for either outcome to interpret.

Missing-data methods and analysis populations are not reported in the registry record. The record does not explain whether all randomized participants were included in any analysis, how incomplete depression ratings were handled, or whether participants were analyzed according to their assigned group. It also does not describe exclusions, withdrawals, or the number assessed for each outcome. These omissions prevent assessment of how missing observations or departures from the planned intervention might affect any estimate.

In general, missing outcomes can create bias when the likelihood of being observed is related to participant characteristics or outcomes. Statistical methods can address some missing-data situations, but their validity depends on assumptions and on clear reporting of who was included and how missingness was handled. No method or assumption can be attributed to this study from the posted registry information.

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.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: er visit for injury (12.5%), er visit for general disorder (12.5%), er visit for respiratory disorder (10.0%).

The serious adverse-event entries list Peer to Peer Clients with 8 participants at risk and 2 affected, and Referral Clients with 10 participants at risk and 1 affected. The other-adverse-event entries list 8 at risk and 0 affected for Peer to Peer Clients, and 10 at risk and 0 affected for Referral Clients. Deaths are recorded as 0 in each group.

The registry also lists “ER visit for injury” and “ER visit for general disorder” at 12.5% each, and “ER visit for respiratory disorder” at 10.0%, among the top serious-event terms. These percentages are reproduced as recorded; the registry entry does not provide additional context for their denominators or explain how the term-level percentages relate to the group counts.

These entries are descriptive, not a formal comparison between groups. The record does not report a statistical test or uncertainty interval for safety outcomes. Counts of participants affected do not necessarily describe the total number of events, since the record does not explain whether individuals could have multiple events. The figures therefore describe what is recorded in the registry, but do not establish that one group had greater or lesser risk.

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

The registry record establishes that the study was designed to examine a peer-delivered Behavioral Activation approach alongside standard mental health referral for depressed older adults in community settings. It describes a randomized, parallel-group comparison, the planned interventions, and a primary outcome centered on whether eligible coaches completed training and certification. It also lists changes in Hamilton Depression Rating Scale Scores as a secondary outcome.

What the record does not establish is the result of the primary endpoint or the size and precision of any difference in client depression scores. It reports no analyses, no primary-outcome estimate, and no secondary-outcome results. The registered enrollment of 29 is not itself a result and does not identify how many eligible coaches were assessed or how many clients contributed data to any particular outcome.

The coach endpoint is an implementation measure rather than a direct clinical outcome. Even if a certification result were available, it would not by itself establish that clients’ symptoms changed or that the peer-delivered intervention was acceptable. Conversely, the lack of a posted result does not show that training failed or that client outcomes did not change. The registry record does not permit either conclusion.

In general, interpreting a treatment comparison requires the estimated group outcomes, the contrast of interest, and the uncertainty around that contrast. Those elements are not reported for the clinical outcome in this record. A randomized design can support a causal comparison when the relevant outcomes and analyses are available and the assumptions are reasonable; randomization alone is not a substitute for reported results.

The safety counts likewise do not establish a comparative safety effect. They should be read as event summaries recorded for the two client groups, with the limitations of the available detail. Overall, the record is informative about the study’s intended question and structure, but insufficient to conclude whether the intervention had a particular effect on clients or whether its outcomes were estimated precisely.

14. Why This Trial Matters Statistically

Statistically, this trial illustrates why the primary outcome must be distinguished from the broad research aim. The study aimed to examine feasibility, acceptability, and preliminary impact, but the registered primary endpoint concerns coach training and certification. That measure can describe an implementation milestone, while client symptom change is a separate question. Treating the two as equivalent would blur the difference between intervention delivery and clinical outcome.

The distinction between a count and a proportion also matters. The endpoint is described as a proportion, yet its unit and parameter are recorded as participants and count. A count can be informative about how many coaches reached certification, but a proportion also needs a clearly defined eligible group. Without a reported count and denominator, neither the absolute result nor the proportion can be assessed.

The record further shows that a randomized two-group client design does not guarantee that every registered outcome has a two-arm comparison. The primary endpoint concerns coaches in the Peer to Peer setting, and the registry notes that fewer than two arms contribute to that outcome. Statistical interpretation must follow the outcome’s actual unit and population, rather than assume that every measure compares the randomized client groups.

Finally, the absence of posted analysis results is an important reporting limitation. A completed study designation and an enrollment figure do not supply estimates, precision, or a basis for evaluating missing data and multiplicity. Separating what the design intended to answer from what the registry reports as results is essential for an accurate statistical reading.

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 provides limited detail about implementation and analysis. It does not state the allocation ratio, randomization procedure, concealment method, or identity of the party masked. It also does not report how many eligible coaches were enrolled, assessed, trained, or certified. This is particularly relevant because the primary endpoint is described both as a proportion and as a participant count.

The primary outcome does not directly measure client depression, and the record contains no posted result for it. The named secondary outcome—changes in Hamilton Depression Rating Scale Scores—has no reported estimate or analysis. The record does not specify measurement timing for the secondary outcome, how change was defined, or which participants contributed data. It also does not describe analysis populations, withdrawals, missing-data handling, or outcome-assessment procedures.

Although the study is recorded as randomized, the record does not supply enough analytic detail to assess whether a reported comparison, if available elsewhere, followed the assigned groups or adjusted for any design features. No analysis plan, interim analysis information, sample-size justification, multiplicity method, or model specification is reported in the registry record. The planning assumptions listed for sample-size illustrations do not establish that those assumptions were used to design this trial.

Safety reporting is similarly limited. The record gives group entries for serious events, other adverse events, and deaths, and lists several serious-event terms with percentages. It does not explain the term-level denominators, event ascertainment, or whether participants could contribute multiple events. No inferential comparison is reported. Finally, the study’s community-based population and intervention description define the setting to which its intended findings would pertain; the registry record does not provide results that would support broader conclusions.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Peer to Peer Delivery of Behavioral Activation — NCT02292849.
• Registry record last updated 2017-09-29; status last verified 2017-08.
• Results first posted 2017-09-29.
• 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

NCT02292849, titled “Peer to Peer Delivery of Behavioral Activation,” is recorded as a completed randomized, single-masked, parallel-group study with enrollment of 29. It concerns depression among older adults aged 60 or older in Naturally Occurring Retirement Communities or senior centers. Peer to Peer participants were to receive standard mental health referral plus 12 weekly peer-coach meetings; Referral participants were to receive standard mental health referral.

The primary outcome concerns eligible Peer to Peer coaches who undergo Behavioral Activation training and achieve certification, with a timeframe of 4 weeks prior to Baseline. Changes in Hamilton Depression Rating Scale Scores are listed as a secondary outcome. The registry record lists 3 outcome measures and zero analyses, and does not report a primary-outcome result or a depression-score result. Safety entries include serious adverse events, other adverse events, and deaths, but no statistical comparison.