Increasing Caregiver Engagement in Juvenile Drug Courts: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Increasing Caregiver Engagement in Juvenile Drug Courts (NCT03051997), a randomized na study. The primary outcome is Number of Participants With Positive Urine Drug Screens at 5 Months Post-baseline.

2. Clinical Question

The study’s stated purpose extends beyond this primary measure. It tests whether a prize-based approach can increase caregiver engagement and seeks to examine longer-term outcomes involving youth substance use and delinquent behavior. Those broader aims are reflected in the listed secondary outcomes, including youth arrests, charges, convictions, delinquent behaviors, internalizing symptoms, and externalizing behaviors. The primary outcome is narrower: a count of participants with positive screens at a specified follow-up. It should not be treated as a direct measure of caregiver engagement or as a complete measure of the study’s longer-term aims.

3. Trial Design

The registry describes a randomized, single-masked, parallel trial of behavioral interventions. The two groups were caregiver contingency management plus usual drug court treatment, and usual drug court treatment alone. The intervention description says that the first group received caregiver contingency management alongside standard outpatient substance abuse treatment services at juvenile drug court; the comparison group received those standard services. The registry does not describe who was masked, so the meaning of single masking for participants, caregivers, clinicians, or outcome assessors is not reported in the registry record.

The study’s enrollment is 53. The primary endpoint summaries list 18 participants for caregiver contingency management plus usual treatment and 13 for usual treatment. The record does not explain the relationship between overall enrollment and the numbers represented in these endpoint summaries, including whether the difference reflects availability of outcome data, eligibility for the endpoint, or another reason. Those details are not reported in the registry record.

The study is listed as completed. Its recorded start date is 2017-10-13, and its primary completion date is 2023-12-12. The phase is listed as NA, and the sponsor is Medical University of South Carolina. These administrative details do not provide information about how allocation was generated or concealed, or about the conduct of follow-up.

The primary outcome is the number of participants with positive urine drug screens at five months post-baseline. The description identifies tests for THC, amphetamines, methamphetamines, opiates, cocaine, benzodiazepines, MDMA, and oxycodone; assessments were made at baseline and five months, with data reported for the five-month time point. The registry also lists secondary outcomes covering youth justice involvement, behavior, caregiver and youth reports of symptoms, caregiver substance use and depressive symptoms, working alliance, attendance, and activity completion. The listed registry record includes 17 outcome measures and 15 posted secondary outcomes, but it has no analysis entries. Details of the statistical design and implementation 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.

Before assignment: This study enrolled adolescent-caregiver dyads. The reported enrollment (n=53) reflects dyads. Outcome and adverse event data were collected only for adolescents unless otherwise noted. Counts represent dyads. Individual counts for adolescents and caregivers were not separately tracked for milestones.

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.

Population: Baseline Measures were only collected for adolescents participants. They were not collected for Caregivers

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Positive Urine Drug Screens at 5 Months Post-baseline, measured over Baseline to 5 months.

The primary endpoint counts participants with positive urine drug screens at five months post-baseline. The registry describes the measure as reflecting positive results for THC, amphetamines, methamphetamines, opiates, cocaine, benzodiazepines, MDMA, and oxycodone. Samples were assessed at baseline and five months, but the result reported for this endpoint is the five-month time point.

A count of participants with an event is a binary-outcome summary: each participant is classified according to whether the defined event was present. This makes the endpoint a direct way to describe how many participants in each arm had at least one positive screen under the registry’s measure. The count does not, by itself, convey how many substances were positive for each participant, the number of positive samples, the frequency or duration of substance use, or change from baseline. Those details are not reported in the registry record.

The endpoint is relevant to the trial’s stated interest in youth substance use, but it is distinct from the study’s caregiver-engagement aim and from its other listed outcomes, such as delinquent behavior and arrests. The registry reports 18 participants with positive screens among 18 represented in the caregiver contingency management arm and 13 among 13 represented in usual treatment. These counts describe the endpoint summaries; they do not explain why the numbers represented in the summaries are smaller than overall enrollment.

The use of urine screening provides an objective test result as defined by the endpoint, but interpretation remains tied to the collection time and substances named in the record. The registry does not report further details about testing procedures, thresholds, confirmation methods, or how missing or unusable samples were handled.

7. Results Posted in the Registry

• Usual Drug Court Treatment: 100.0% (13/13) versus 100.0% (18/18) on control; risk difference 0.0 percentage points (95% CI 0.0 to 0.0), risk ratio 1.00 (1.00–1.00); unadjusted two-proportion z-test p = n/a.

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the study as randomized, single-masked, and parallel, with two behavioral intervention groups. Randomization is intended, in general, to make groups comparable on average at assignment; it does not guarantee that every observed feature will be balanced in a particular trial. A parallel design assigns participants to a group whose intervention is followed over the study rather than crossing participants between interventions. The record does not explain the randomization sequence, allocation concealment, masking procedures, or which people were masked.

What does the endpoint count?

The endpoint is a count of participants with at least one positive urine drug screen at five months. For statistical purposes, this is a binary outcome at the participant level: the measure records whether the defined positive-screen event occurred. The registry’s list of substances specifies what the endpoint covers, but the count does not show the number of positive substances or the number of positive samples per participant. It also does not show the timing of any positive result between scheduled assessments.

For a binary outcome, an arm’s event count can be interpreted alongside the number of participants represented in that arm. Here, the registry reports 18 positive results among 18 participants for caregiver contingency management plus usual treatment, and 13 among 13 for usual treatment. Both arm summaries therefore display the event for every represented participant. The overall enrollment is 53, while the endpoint summaries include 18 and 13 participants. Reasons for the difference, such as missing observations or a different analysis population, are not reported in the registry record and should not be inferred.

How should the risk difference be understood?

A risk difference compares the event proportions in two groups by subtracting one group’s proportion from the other. It is expressed on the same probability scale as the event proportions. As a general statistical concept, a risk difference of zero means that the observed proportions are equal under the calculation being reported. In this trial’s posted endpoint summaries, both groups have all represented participants classified as having positive screens; the recalculated risk difference is 0.0. The record also gives a confidence interval from 0.0 to 0.0 and p = 1.0.

These statistics are unadjusted recalculations from the posted summary counts. They do not account for other participant characteristics, repeated observations, clustering, or other factors through a model. No adjusted analysis is posted. The comparison’s confidence interval and p-value should therefore be understood in the context of the simple calculation, not as the result of a documented sponsor model. A p-value is a measure of how compatible data are with a specified null hypothesis under a particular statistical procedure; it is not the probability that the null hypothesis is true, and it does not measure clinical importance.

Why is the interval not informative about population precision?

A confidence interval is a range generated by a statistical procedure to express uncertainty about an estimated quantity. In general, its meaning depends on the model and assumptions used to calculate it. Here, no participant in either endpoint summary is classified as screen-negative, so the binary outcome has no observed variation within either arm. The posted interval has identical lower and upper limits, 0.0 and 0.0. That displayed precision should not be mistaken for strong evidence that the population difference is known exactly. It reflects the behavior and limitations of the unadjusted calculation with these counts, rather than resolving uncertainty about outcomes beyond the observed participants.

In general, when a binary endpoint has event outcomes in every observed participant, standard methods can encounter boundary estimates or yield intervals that do not capture uncertainty well. Alternative methods may be considered in an analysis plan, but the registry does not report a prespecified method, an alternative calculation, or the sponsor’s reasoning. No new inferential result can be substituted for the posted figures without further data and a specified method.

What is known about analysis planning?

The registry record lists 17 outcome measures and 15 posted secondary outcomes, while the number of analysis entries is zero. It does not report a statistical analysis plan, model specifications, covariate adjustments, interim analyses, or a sample-size justification. The stated sample-size illustration assumptions describe a two-sided significance level of 0.05, equal allocation, and a normal approximation, with planning effects expressed as fractions of the observed effect. Such illustrations are planning scenarios, not observed power and not proof that the trial was designed or analyzed according to those assumptions. No resulting planning sample sizes are available in the record.

In general, binary outcomes can be analyzed with methods that estimate event probabilities or compare those probabilities between groups. Which approach is suitable depends on the design, amount of information, and analysis population, among other considerations. The registry does not identify a method used by the sponsor, so no such method should be attributed to this trial. The posted arm counts and recalculation permit only a limited descriptive comparison.

10. Confidence Intervals and Precision

The posted risk difference is 0.0, with a confidence interval from 0.0 to 0.0. This is the interval accompanying the unadjusted recalculation from the arm summaries. The displayed interval has no width, but that appearance should not be taken to mean the treatment contrast is known with exact precision for the population of interest.

Confidence intervals express uncertainty under a specified calculation and its assumptions. In general, precision depends on the amount and pattern of information in the data, as well as the method used. In this case, all participants represented in both arm summaries had the binary event: 18 of 18 and 13 of 13. With no screen-negative participants in either summary, the observed data contain no within-arm variation for this outcome. That boundary pattern limits what the simple recalculation can say about uncertainty beyond the observed participants. A zero-width interval is therefore a property of the reported calculation, not a guarantee of a zero difference in the population.

The registry record contains no sponsor analysis entries or method details that would support a more complete assessment of uncertainty. It does not report an adjusted interval, an alternative interval method, or a model accounting for other features of the study. The reason that the endpoint summaries include fewer participants than overall enrollment is also not reported. Without those details, it is not possible to assess whether the interval reflects the intended analysis population or how any unavailable endpoint data might affect precision.

The value p = 1.0 does not fill this gap. It describes the recalculated comparison under its procedure; it is not a measure of the probability that the observed contrast is correct and does not demonstrate equivalence. The most defensible reading is narrow: the posted endpoint summaries show identical observed proportions, and the simple recalculation reports a risk difference of 0.0 with the interval and p-value stated above. The precision of any broader treatment effect is not established by those figures.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists a broad set of secondary outcomes as well as the primary urine-screen endpoint. The secondary outcomes include youth arrests, charges, convictions, delinquent behaviors, caregiver and youth reports of internalizing symptoms and externalizing behaviors, caregiver substance use problems and depressive symptoms, therapist-family working alliance, and caregiver treatment attendance and activity completion. The record lists 17 outcome measures and 15 posted secondary outcomes, but contains zero analysis entries.

When a study evaluates multiple outcomes or repeated measurements, general statistical practice considers multiplicity: the chance of obtaining apparently notable results can increase when many comparisons are examined. Researchers may address this through a prespecified hierarchy, adjusted significance thresholds, or other strategies. Whether any such strategy was planned or used in this trial is not reported in the registry record. No multiplicity adjustment can therefore be attributed to the posted primary comparison, and no conclusions about secondary-outcome significance can be drawn from the outcome descriptions alone.

The registry describes several secondary outcomes as measured repeatedly across follow-up times. Repeated measurements can require methods that account for the relationship between observations from the same participant. The record does not specify models, handling of repeated observations, or which time points were treated as primary for each secondary analysis. It does not report interim analyses or stopping rules.

Missing-data handling and analysis populations are also not reported in the registry record. Overall enrollment is 53, while the primary summaries list 18 and 13 participants. The record does not explain why those are the numbers represented in the endpoint result, whether any outcomes were missing, or whether the summaries correspond to all randomized participants, participants with available results, or another defined population. No imputation procedure, sensitivity analysis, or intention-to-treat statement is reported. These omissions limit interpretation of both the endpoint comparison and the relationship between enrollment and the posted result.

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

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: suicide attempt (14.3%).

The registry reports serious adverse events among adolescents in both groups. For caregiver contingency management plus usual drug court treatment, 32 adolescents were listed as at risk and 3 as affected by serious adverse events. For usual treatment, 21 were listed as at risk and 3 as affected. The registry lists suicide attempt as a top serious adverse event term, with 14.3%. That percentage is presented as the registry’s term-level figure; the record does not explain its denominator or calculation in the information.

Other adverse events were recorded for 1 of 32 adolescents in the caregiver contingency management group and 0 of 21 in usual treatment. The registry reports 0 deaths in both groups. These safety summaries are separate from the primary urine-screen endpoint and should not be combined with it. The risk counts describe the groups listed in the adverse-event record and do not necessarily identify the same analysis population as the primary endpoint summaries.

Adverse-event counts alone do not establish cause. The registry data do not state whether events were judged related to an intervention, provide event narratives, or describe how serious-event categories were defined or collected. The figures should therefore be read as the recorded counts, not as evidence that an intervention caused or prevented an event. The event totals are small, and the record does not report a formal comparative safety analysis or uncertainty estimates.

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

The posted primary result describes positive urine screens at five months among the participants represented in the endpoint summaries. The registry reports 18 of 18 participants in caregiver contingency management plus usual treatment and 13 of 13 in usual treatment with positive screens. The unadjusted recalculation reports a risk difference of 0.0, an interval from 0.0 to 0.0, and p = 1.0. The observed proportions are identical in these summaries.

This result does not demonstrate that the interventions are equivalent. A finding of no observed difference is not the same as evidence that any true difference is absent or sufficiently small. Equivalence or non-inferiority requires a design and analysis addressing a prespecified margin; neither is described in the registry record. The all-positive pattern also means the comparison offers little observed variation with which to assess differences in the broader population.

The primary endpoint does not directly measure caregiver engagement, despite the study’s stated focus on increasing caregiver participation. It also does not summarize the full course of youth substance use, since the reported endpoint is at five months and the registry description does not provide counts of positive samples or substances per participant. The listed secondary outcomes concern important additional domains, but outcome descriptions alone do not show whether those outcomes changed or differed between groups. Their analyses are not posted in the registry record.

The overall enrollment is 53, whereas the primary endpoint summaries list 18 participants in one arm and 13 in the other. Since the record does not explain this difference, the endpoint figures cannot be assumed to represent every enrolled participant or used to infer why other participants are not represented. Missingness and analysis-population details are not reported.

The result is thus a limited description of the posted five-month endpoint counts and their simple comparison. It should not be extended to the trial’s secondary outcomes, to overall caregiver engagement, or to a causal conclusion about treatment effects. The record’s lack of analysis entries and uncertainty about the endpoint population are central constraints on interpretation.

14. Why This Trial Matters Statistically

This trial presents a useful statistical example of why an estimate must be read together with its data structure. For a binary endpoint, the two arm summaries show the event in every participant represented. The observed proportions are consequently identical, and the unadjusted risk difference is 0.0. Yet the identical proportions and reported zero-width confidence interval do not settle the question of what difference might exist beyond these observed participants. When an outcome has no within-arm variation, a simple comparison can look more precise than the underlying evidence warrants.

The study also distinguishes an intervention’s stated target from its primary endpoint. Caregiver contingency management is intended to increase caregiver engagement, while the primary outcome counts youth with positive urine drug screens at five months. Those are related to the trial’s broader purpose but are not interchangeable outcomes. Statistical interpretation must remain tied to what was actually measured and posted.

Finally, the gap between overall enrollment and the participants listed in the primary summaries matters. Without an explanation of the endpoint population, missing outcomes, or analysis set, readers cannot determine why the primary result represents fewer participants than enrollment. The registry also lists many secondary outcomes but no analysis entries, leaving multiplicity decisions and the analysis of repeated observations undocumented. These features illustrate why transparent reporting of denominators, analysis populations, and methods is essential alongside outcome counts.

The practical statistical lesson is not to infer more than the record supports. The posted numbers permit a narrow descriptive statement about the five-month endpoint and its unadjusted comparison. They do not establish equivalence, resolve uncertainty about the broader population, or answer every question motivating the study.

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.

Several trial-specific limitations constrain interpretation of the posted endpoint. Overall enrollment is 53, but the primary result lists 18 participants in the caregiver contingency management group and 13 in usual treatment. The registry record does not explain the discrepancy between enrollment and these endpoint denominators. It is not possible to determine from the record whether this reflects missing outcome data, a defined subset, or another reason. The effects of unavailable or unreported endpoint data therefore cannot be assessed.

The primary outcome has no observed variation in either arm: all participants represented in each summary had positive urine screens. This boundary pattern makes the displayed unadjusted risk difference of 0.0 and interval from 0.0 to 0.0 difficult to interpret as population precision. The record does not supply a sponsor analysis or an alternative method for evaluating the result under this pattern. Its analysis entries are zero.

The registry identifies the design as randomized, single-masked, and parallel, but does not report how randomization was implemented, who was masked, or whether allocation was concealed. It also does not report a statistical analysis plan, the prespecified analysis population, missing-data methods, multiplicity procedures, or interim analyses. No sample-size justification is reported. The planning assumptions listed in the record are illustrations based on an observed effect, not evidence of the trial’s own design rationale or observed power.

The primary endpoint is limited to positive urine screens at five months. The registry does not provide further testing procedures or the number and pattern of positive substances or samples for each participant. The broader study purpose includes caregiver engagement and longer-term youth outcomes, but the record’s outcome descriptions do not provide posted analyses for those aims. These limitations mean the available result should be interpreted narrowly, without claims about unreported outcomes or the reasons behind the endpoint denominators.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Increasing Caregiver Engagement in Juvenile Drug Courts — NCT03051997.
• Registry record last updated 2026-08-07; status last verified 2026-07.
• Results first posted 2025-12-08.
• 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

NCT03051997 is a completed randomized, single-masked, parallel behavioral trial titled Increasing Caregiver Engagement in Juvenile Drug Courts. It compared caregiver contingency management plus usual drug court treatment with usual treatment alone. Overall enrollment was 53. The recorded start date was 2017-10-13, and primary completion was 2023-12-12.

The primary outcome was the number of participants with positive urine drug screens at five months post-baseline. The registry reports 18 of 18 in the caregiver contingency management arm and 13 of 13 in usual treatment. Its unadjusted comparison gives a risk difference of 0.0, a confidence interval from 0.0 to 0.0, and p = 1.0. The registry record contains no analysis entries and does not explain why the endpoint summaries include fewer participants than overall enrollment.

Serious adverse events affected 3 of 32 adolescents in the intervention group and 3 of 21 in usual treatment; deaths were 0 in both groups. Statistical analysis details, missing-data handling, and secondary-outcome analyses are not reported in the registry record.