Refining the Shared Decision Making Process Survey in ADHD Medication Decisions: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Refining the Shared Decision Making Process Survey in ADHD Medication Decisions (NCT05048186), a registered phase not stated study. The primary outcome is Shared Decision Making Process Score.

2. Clinical Question

3. Trial Design

This completed study is described as a retrospective observational survey of adults who were parents or legal guardians of a child with ADHD. Eligible participants had discussed ADHD treatment options with a health care provider within the last 2 years. The registry lists an enrollment of 512 and Massachusetts General Hospital as the sponsor. The study began on 2021-02-24, and primary completion was recorded as 2021-03-23.

The survey included the Shared Decision Making Process measure and other measures. The study description says participants would be randomized to review the ADHD Decision Aid partway through the survey or to receive no educational materials. However, the allocation method is not stated in the registry record, and the posted arm information cautions that the arms are not a like-for-like control comparison. The record therefore does not support treating the arm contrast as a clearly documented randomized comparison.

The primary outcome concerns participants’ reported shared decision making during discussions in the last 24 months. Secondary measures include ADHD knowledge, decisional conflict, decision regret, treatment choice, a Vanderbilt Assessment Performance Sub-scale, an adapted preference scale, and a retest of the shared decision making measure. A subset was intended to complete a retest survey about two weeks after the initial survey. Whether that retest was completed, and the resulting estimates, are not reported in the registry record.

The stated study goals include gathering evidence about the scale’s validity and reliability, the quality of parents’ decisions, and the possible effect of a Decision Aid on knowledge. These aims require different interpretations: a scale’s measurement properties are not the same question as whether an educational intervention changes knowledge. The registry record does not give a detailed statistical analysis plan or report results for these aims.

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: Eligible participants were caregivers who self-identified as having at least one child between the ages of 5 and 13 years old with ADHD and who had talked with a health care provider about starting, stopping, or changing an ADHD medicine in the last 2 years.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: participants who provided enough information to calculate a shared decision making process score (primary outcome of interest). 498/498 patients provided an answer to this question.

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: Participants provided enough information to calculate the shared decision making process score (primary outcome of interest). Participants were not included in the analytic dataset if they provided inconsistent answers (e.g. indicating their main decision was to start taking medication but they reported their child was not on medication currently and had not been on medication in the past)

6. Primary Endpoint

The registry lists the primary outcome as Shared Decision Making Process Score, measured over baseline survey (reflecting on the last 24 months).

The primary endpoint is the Shared Decision Making Process Score, a continuous measure reported as a mean with a standard deviation. The scale is described as a short patient-reported survey measuring the amount of shared decision making in an interaction. Scores range from 0-4, with higher values indicating that a better shared decision making process occurred. The endpoint reflects participants’ recollections of discussions during the last 24 months, rather than a direct observation of the clinical interaction.

This measure is relevant to the study’s main aim because the investigators sought evidence about the scale’s validity and reliability. Validity concerns whether a measure captures the concept it is intended to represent; reliability concerns whether its measurement is consistent under relevant conditions. A score distribution or a difference between arms, by itself, cannot establish both properties. Such interpretation depends on the analysis and supporting evidence, which are not reported in the registry record.

The primary outcome population is described as participants with enough information to calculate the score, and the registry states that 498/498 patients answered the question. Answering the question does not, on its own, establish the score distribution, the number with a calculable score under every scoring rule, or the precision of an estimated mean. The registry record does not report the primary mean, standard deviation, confidence interval, or an arm-specific estimate. The endpoint’s scale and direction can therefore be described, but its observed level and uncertainty cannot be interpreted from the record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is a continuous score summarized in the registry as a mean and standard deviation. These statistics answer different questions. A mean describes the central level of scores in a group, while a standard deviation describes how dispersed individual scores are around that mean. Neither statistic is reported for this outcome in the registry record, so the average level and observed spread cannot be characterized.

What would a confidence interval convey?

In general, a confidence interval expresses the statistical uncertainty around an estimated quantity, such as a mean or a difference between group means. A narrower interval indicates greater precision under the analysis assumptions; a wider interval indicates less precision. An interval does not show the range of individual participants’ scores. The registry record does not report a confidence interval for the primary score or an arm contrast, so precision cannot be evaluated.

How should an arm comparison be understood?

In general, an unadjusted comparison of continuous outcomes might describe the difference between group means, while an adjusted analysis may account for measured characteristics specified in an analysis plan. The choice of analysis depends on the design, outcome distribution, and prespecified methods. The registry record does not report the primary mean by arm, a between-arm estimate, a confidence interval, a p-value, or a statistical model. It also does not report an adjustment plan. No arm effect can therefore be quantified from the registry record.

The study summary describes random assignment to a Decision Aid Arm or a Control Arm. However, the allocation method is not stated in the registry record, and the posted arm information cautions that the comparison is not like-for-like. In general, a causal interpretation of a group contrast depends on the design and implementation of group assignment, along with appropriate outcome measurement and analysis. The available record does not provide enough detail to establish those conditions for this comparison.

What does the scale’s bounded range imply?

The score ranges from 0-4, and higher values indicate a better reported shared decision making process. In general, a bounded scale cannot take values outside its defined endpoints. When interpreting a mean and standard deviation for such a measure, the observed distribution can matter: a mean may conceal clustering near an endpoint or differences in score shape. The registry record does not provide a distribution, quantiles, or other descriptive statistics, so distributional features cannot be assessed. No assumption about a particular distribution should be attributed to the analysis.

In general, over-dispersion refers to variability greater than a model expects, and it can affect uncertainty estimates when the model does not account for it. The registry record does not identify a model for the primary outcome or report a distributional assessment. This is a general statistical consideration, not a finding about this study.

How do reliability and validity relate to this endpoint?

Reliability concerns the consistency of measurement; validity concerns whether evidence supports the intended interpretation of a measure. The study’s main stated goal was to gather evidence about both for the Shared Decision Making Process scale. A retest in a subset about two weeks after the initial survey was described as part of the study. In general, retest evidence requires information about paired responses and a specified reliability analysis. The registry record does not report the retest results, the number who completed it, or a reliability statistic. It also does not report validity analyses or the evidence used to support a validity argument.

The study’s other stated goals concern decision quality and the potential impact of a Decision Aid on knowledge. Those goals involve distinct outcomes and interpretations. A knowledge comparison would not by itself establish scale reliability, and a score on the shared decision making measure would not by itself establish improved decision quality. The listed secondary outcomes include ADHD knowledge, decisional conflict, decision regret, treatment choice, a Vanderbilt Assessment Performance Sub-scale, an adapted preference scale, and the retest measure, but their estimates are not reported.

What do planning illustrations mean?

In general, a sample-size planning illustration shows how a proposed design might perform under specified assumptions about an effect and analysis. The record describes planning assumptions that include a two-sided significance level of 0.05, equal allocation, a normal approximation, and an effect defined as a fraction of the observed effect. It also states that the illustration is based on the observed effect rather than the trial’s own design. No planning counts or observed effect estimate are reported in the registry record.

Such planning values are not observed outcomes and do not establish the power of a completed study. In particular, a retrospective illustration based on an observed effect should not be read as observed power or as evidence that the study was designed to detect that effect. The registry record does not report the study’s own sample-size justification. It also does not report interim analyses or a detailed statistical analysis plan.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Decision Aid Arm", "Control Arm")
n   <- c(242, 256)
m   <- c(2.83, 2.77)
sp  <- c(1.06, 1.04)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Decision Aid Arm  242  2.830  1.060  2.696  2.964
CARM  Control Arm  256  2.770  1.040  2.642  2.898

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists nine outcome measures and one analysis. It does not report whether statistical tests across outcomes were adjusted for multiplicity, whether outcomes were organized into prespecified testing families, or whether any hierarchy of primary and secondary hypotheses was used. In general, examining multiple outcomes can increase the chance of at least one apparently notable result by chance; adjustment methods or a prespecified interpretation strategy can address that issue. The record does not state such a strategy, so the handling of multiplicity is not reported in the registry record.

The primary outcome description says 498/498 patients answered the question and defines the primary population as participants who provided enough information to calculate a score. Those details do not describe missingness for every other measure, nor do they show how incomplete responses were handled in the analysis. The record does not report imputation methods, complete-case rules, or sensitivity analyses for missing data. Retest completion and missingness in the retest subset are also not reported.

The enrollment is listed as 512, but the registry does not provide a full accounting of participants by analysis population, outcome, or arm. It does not report exclusions from a particular analysis or the number contributing to each secondary result. A count of survey answers is not necessarily the same as a count with a calculable outcome or inclusion in every analysis.

The record describes randomization in its study summary, but does not state the allocation method. It also cautions that the arms are not a like-for-like control comparison. The analysis population definitions, handling of deviations from assigned groups, and adjustment strategy are not reported in the registry record. These omissions limit assessment of the analysis and of any group comparison.

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.

The registry lists 242 participants at risk in the Decision Aid Arm and 256 in the Control Arm. It reports zero serious adverse events, zero other adverse events, and zero deaths in each arm. No top serious adverse event terms are listed. These figures describe the entries recorded in the registry; they should not be read as proof that no event of any kind occurred or that the intervention has been established as free of risk.

The study is described as a survey with an educational Decision Aid, rather than a treatment trial evaluating a medication. The registry record does not report details about adverse event collection, the specific observation period for safety, or the criteria used to classify events. It also does not provide further context for the at-risk counts beyond the arm entries. The zero counts are therefore best interpreted narrowly as the reported serious event, other event, and death counts for the listed groups.

In general, an absence of recorded events can reflect the event definitions, observation period, and completeness of reporting as well as the underlying occurrence of events. Those details are not reported in the registry record. The safety entries do not provide evidence about whether the Decision Aid changed survey responses or participant knowledge, and they do not resolve the missing outcome results for the study’s stated aims.

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

The registry record describes a study intended to examine a measure of shared decision making in ADHD medication discussions, with additional aims concerning decision quality and a Decision Aid’s impact on knowledge. It defines the primary score and its direction: scores range from 0-4, and higher values indicate a better reported shared decision making process. It also identifies the target population and states that 498/498 patients answered the primary outcome question.

The record does not report the primary score’s mean or standard deviation, a confidence interval, or a group comparison. It therefore does not show the observed level of shared decision making or the precision of an estimate. It also does not report results for the secondary outcomes or evidence about the scale’s validity and reliability. The stated study aims should not be mistaken for findings.

The study summary describes randomization, but the allocation method is not stated, and the posted arm information says the groups are not a like-for-like control comparison. For that reason, the record does not support a firm causal interpretation of any difference between the Decision Aid and Control Arms. In addition, no effect estimate is reported to quantify a difference in the first place.

In general, a survey score is a measure of a reported experience, not a direct measure of every aspect of a clinical interaction or the quality of a treatment decision. This study’s primary score reflects participants’ accounts of discussions during the last 24 months. The registry record does not report whether the measure’s performance was consistent across participant subgroups or settings.

The record can establish what the study set out to measure and how the endpoint is defined, but not whether the Decision Aid changed knowledge, whether decisions were of higher quality, or whether the instrument met its measurement aims. Those conclusions require results and analyses that are not reported in the registry record.

14. Why This Trial Matters Statistically

This study raises a useful statistical distinction between evaluating a measurement instrument and evaluating an intervention. The Shared Decision Making Process Score is the primary measure, while the Decision Aid is an educational intervention described in the study summary. Evidence that a scale measures shared decision making consistently or validly addresses a different question from evidence that educational material changes participant knowledge.

That distinction matters because a score’s interpretation depends on more than its numerical range. The registry defines the scale’s endpoints and direction, but assessment of measurement performance would require reported analyses. The planned retest could inform repeatability, while analyses of how scores relate to other measures could contribute to validity evidence. The registry record does not report those estimates or the analyses used.

The study also illustrates why design details matter when comparing groups. The summary describes randomization, yet the allocation method is not stated and the posted arm information cautions that the groups are not a like-for-like control comparison. Without a clear account of allocation and analysis, a group difference—if reported—would need careful interpretation. Here, the record does not report a primary group contrast at all.

Finally, complete answers to a survey question do not replace outcome estimates. The record says 498/498 patients answered the primary question, but does not report the resulting score distribution or its uncertainty. Transparent outcome summaries, analysis populations, and missing-data methods would be needed to assess precision and determine how well the findings address the study’s stated goals. The registry record leaves those statistical results unreported.

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 primary score is retrospective and reflects discussions during the last 24 months. In general, recalling prior conversations can introduce error, and the registry record does not report an assessment of recall accuracy. The study population is limited by its stated eligibility description to adult parents or legal guardians of a child diagnosed with ADHD who had discussed treatment options with a health care provider. The record does not provide demographic details or information about how representative participants were of that population.

The registry describes a Decision Aid Arm and a Control Arm, but does not state the allocation method. It also says the arms are not a like-for-like control comparison. This limits interpretation of between-arm findings, especially for causal questions. No primary outcome estimates or secondary outcome results are reported, so the size and precision of any observed differences cannot be assessed.

The main goal was to gather evidence about the scale’s validity and reliability, but the registry record does not report the relevant analyses. A retest was planned for a subset about two weeks after the initial survey, yet completion and results are not reported. The record also does not describe scoring details beyond the scale range and direction or provide outcome distributions.

Other limitations of interpretation arise from unreported analysis information. The statistical plan, handling of missing data, analysis populations, multiplicity approach, and sample-size justification are not reported in the registry record. Although enrollment is listed as 512 and the primary question response count as 498/498, the record does not account for participant contributions across all measures and analyses. These gaps prevent a detailed assessment of analysis choices and the scope of the results.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Refining the Shared Decision Making Process Survey in ADHD Medication Decisions — NCT05048186.
• Registry record last updated 2024-11-21; status last verified 2024-10.
• Results first posted 2024-11-21.
• 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

NCT05048186 is a completed retrospective observational survey study sponsored by Massachusetts General Hospital. The listed enrollment is 512. The study began on 2021-02-24, and primary completion was recorded as 2021-03-23. It concerns parents’ or legal guardians’ reports of ADHD treatment discussions for a child.

The primary outcome is the Shared Decision Making Process Score, a mean on a scale ranging from 0-4, with higher scores indicating a better reported process. The record states that 498/498 patients answered the primary outcome question. The study description includes a Decision Aid Arm and a Control Arm, but the allocation method is not stated and the arms are not identified as a like-for-like control comparison.

The study’s stated aims include gathering evidence about the scale’s validity and reliability, decision quality, and the possible impact of a Decision Aid on knowledge. The registry record does not report primary or secondary outcome estimates, measurement-property findings, or a detailed statistical analysis plan. It reports zero serious adverse events, zero other adverse events, and zero deaths in each arm.