This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Development of a Mobile App for an Executive Functioning Intervention for Adolescents (NCT04018794), a na na study. The primary outcome is System Usability Scale.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04018794 |
| Phase | NA |
| Condition | Attention Deficit Hyperactivity Disorder Symptoms |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 15 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of California, San Francisco |
| Results posted | Yes |
2. Clinical Question
Population
Adolescents with Attention Deficit Hyperactivity Disorder Symptoms were the population named in the registry record. The record describes development of a mobile tool for adolescents receiving clinician-directed behavioral and organizational skills treatment. It does not report further eligibility details or a more specific description of the participants.
Intervention
The intervention combined behavioral and organizational skills treatment with a mobile application. The arm description specifies 16 sessions lasting 20-30 minutes, twice weekly for 8 weeks. The stated purpose of the app was to support the treatment, with development guided by input from key stakeholders.
Comparator
There was no separate comparator group. The registry record describes a single-group study and lists allocation as NA. It is therefore not a randomized comparison, and the intervention group cannot be compared with a like-for-like control group using this record.
Primary question
The primary measure was the System Usability Scale (SUS), a score assessing technology product usability. The stated assessment time was month 3, described as 1-month post-intervention. The registry record does not report the observed SUS score, its variability, or an analysis result, so it does not answer how usable participants found the app.
3. Trial Design
This completed study focused on development of an initial mobile app prototype, rather than on a randomized test of treatment effectiveness. The registry identifies the design as single group, with allocation listed as NA and masking listed as none. One intervention group is described: behavioral and organizational skills treatment plus a mobile application. No control arm or alternative intervention is recorded.
The listed intervention schedule was 16 sessions of 20-30 minutes, twice weekly for 8 weeks. The app was intended to augment clinician-directed skills treatment for adolescents with ADHD symptoms. The study summary says prototype development was guided by input from key stakeholders. The registry record does not describe additional details of that development process, the role of each stakeholder, or how feedback informed app changes.
The recorded enrollment is 15. The study start date is 2019-09-30, and primary completion is listed as 2020-09-01. The record marks the study as completed. Its primary outcome is the SUS score at month 3, described as 1-month post-intervention. Four outcome measures are listed, but the record contains no analysis entries. The SUS outcome value and its statistical analysis are not reported in the registry record.
Because there is one group and no recorded comparator, changes over time cannot be separated from other possible influences using a between-group contrast. The design can describe the intervention and its planned usability assessment, but the registry entry does not provide results that quantify usability or establish comparative effects.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: All participants were assigned to a single-arm/group where they all evaluated the usability and feasibility of the ATOM intervention tool as designed. None were excluded upon enrollment.
Overall Study
| Stage | Behavioral/Organizational Skills Intervention Plus Mobile App |
|---|---|
| STARTED | 15 |
| COMPLETED | 15 |
| NOT COMPLETED | 0 |
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.
| Characteristic | Unit | Behavioral/Organizational Skills Intervention Plus Mobile App |
|---|---|---|
| Participants analysed | 15 | |
| Age, Categorical: <=18 years | Participants | 15 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 |
| Age, Categorical: >=65 years | Participants | 0 |
| Sex: Female, Male: Female | Participants | 7 |
| Sex: Female, Male: Male | Participants | 8 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 2 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 13 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 4 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 6 |
| Race (NIH/OMB): White | Participants | 4 |
| Race (NIH/OMB): More than one race | Participants | 1 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 15 |
6. Primary Endpoint
The registry lists the primary outcome as System Usability Scale, measured over at month 3 (1-month post-intervention).
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Full Range |
| Unit | score on a scale |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the System Usability Scale (SUS), recorded as a mean score on a scale with the full range reported. The registry describes the SUS as a 10-item, technology-agnostic measure of technology product usability. Its total score ranges from 0 to 100, with higher scores indicating higher usability. The description states that scores above 80 indicated good usability.
A usability scale is relevant in a prototype-development study because it captures users’ assessments of how usable a technology product is. This is distinct from measuring whether a treatment changes symptoms or other clinical outcomes. The SUS description also notes high internal consistency (α=.91) and high convergent validity with a separate rating of usability and user satisfaction (r=.8). These are scale properties stated in the registry, not results from this study.
The planned assessment was at month 3, described as 1-month post-intervention. The registry record does not report the observed mean SUS score, the number contributing to that endpoint, or a measure of uncertainty. Therefore, the endpoint definition and its intended interpretation are available, but the study’s measured usability result is not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes that this was a completed, single-group study of an initial mobile app prototype intended to support clinician-directed behavioral and organizational skills treatment for adolescents with ADHD symptoms. It records enrollment of 15 and describes the intervention schedule. Its primary outcome was usability, measured using the SUS at month 3, described as 1-month post-intervention.
The key statistical distinction is between a planned endpoint and a reported result. The record defines the SUS, its score range, and the interpretation that scores above 80 indicated good usability. However, it does not report the observed SUS mean, a standard deviation or other measure of spread, a confidence interval, or an analysis result. It is not possible to determine the level or precision of usability from the registry record. The scale’s stated properties do not substitute for the study’s own endpoint estimate.
The record lists four outcome measures and zero analyses. That means the entry contains no registered analysis results to interpret, rather than evidence of a particular estimate or statistical finding. Study status is completed, but completion alone does not supply endpoint results. The absence of a reported value should not be interpreted as a low score, a high score, or a null result.
The single-group design also defines what the study could establish. With no separate comparator, there is no randomized contrast in this record. Even if an endpoint value were available, it would describe the enrolled group’s usability assessment at the stated time; it would not establish how usability compared with another app, treatment approach, or control condition. Nor would a usability score by itself answer whether clinical symptoms or functioning changed.
The registry’s adverse-event summary lists zero participants affected by serious adverse events, zero affected by other adverse events, and zero deaths in the intervention group, with 15 at risk for each listed category. These are the recorded safety figures, not proof that no unrecorded events occurred. The record does not report the methods used to collect or verify adverse events.
Overall, the registry describes the study design, intervention, planned usability assessment, and safety counts, but does not provide analysis results. Conclusions about observed usability, its uncertainty, or changes in clinical outcomes are therefore not reported in the registry record. The study should be read as a development and usability-assessment study with an unreported primary result, not as evidence from a controlled effectiveness comparison.
9. Statistical Methods Explained
The statistical information in the registry entry is limited. It identifies a primary outcome and a single-group design, but lists zero analyses. The registry record does not report a statistical analysis plan, a sample-size justification, interim analyses, or an outcome estimate. The concepts below explain how such information is generally interpreted; they do not describe analyses documented for this study.
What does a mean score describe?
As a general statistical concept, a mean summarizes the central value of a set of scores. For the SUS, the registry specifies a mean score and a scale range of 0 to 100. A mean can give a concise description of group-level usability ratings, but it does not show whether individual ratings were tightly clustered or widely spread. A measure of variability, such as a standard deviation or range, would add information about how participants’ scores differed. Neither a mean nor a variability estimate is reported for this study.
What would a confidence interval add?
In general, a confidence interval expresses uncertainty around an estimate under the assumptions of the analysis used to calculate it. A narrower interval indicates greater precision under those assumptions; a wider interval indicates less precision. It is not a range containing every participant’s score, and it does not remove potential sources of bias. The registry record does not report a confidence interval for the SUS outcome, so the precision of any study estimate cannot be assessed from the entry.
Why does the single-group design matter?
In general, a one-group study can describe observations in that group, but it lacks a concurrent control group for estimating a between-group treatment contrast. A score measured after an intervention does not by itself distinguish the intervention’s contribution from other influences. Here, the registry describes a single-group intervention and no comparator. It is therefore inappropriate to interpret the record as a randomized comparison or as a controlled estimate of treatment effect.
What is the role of the SUS threshold?
The registry description says SUS scores above 80 indicated good usability. This provides a stated interpretive reference for the scale. It does not give the study’s score, and the threshold is not a result. To assess the observed usability, readers would need the actual score and information about its precision and the participants whose scores contributed to it. Those results are not reported in the registry record.
How should missing analysis details be read?
As a general principle, an analysis plan clarifies which outcomes and comparisons were intended, how missing observations would be handled, and what statistical procedures would be used. Without those details, readers should not infer that a particular model, adjustment, or missing-data method was applied. The registry record does not report a statistical plan or analysis entries. It also does not describe interim analyses or a sample-size justification. These omissions leave the analytic approach and rationale unreported; they do not establish that a method was or was not used outside the registry entry.
What can the adverse-event counts establish?
In general, adverse-event counts summarize events recorded under the study’s collection and reporting procedures. Counts are most informative when the record also explains how events were defined, collected, assessed, and followed. The registry lists zero affected participants for serious adverse events, other adverse events, and deaths in the intervention group. It does not provide detailed collection procedures or event narratives. These summary values describe the registry entry and should not be expanded into a claim about all possible events.
There are no reported effect calculations to interpret, and no recalculated comparison is available from the registry entry. The intervention has no comparator arm, and the primary SUS result is absent. Consequently, concepts such as a treatment-effect estimate, a between-group confidence interval, or a statistical test result cannot be applied to a study result that is not reported. Statistical interpretation is limited to the design and outcome definitions that are recorded.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists four outcome measures, identifies the SUS as primary, and records zero analyses. It does not report the other outcome definitions or results in the information available for this study entry. The relationship between the listed measures, any planned hierarchy among them, and the analyses intended for each is not reported in the registry record.
Multiplicity is a general statistical concern when several outcomes or analyses are examined. Repeated testing can increase the chance of finding a result that appears notable by chance. Researchers may address that concern through a prespecified hierarchy or other methods, but the registry record does not report a multiplicity procedure or a detailed statistical plan. No correction or adjustment should be assumed.
The entry also does not report how missing outcome data were handled, whether all enrolled participants contributed to the SUS assessment, or which analysis population was used. The recorded enrollment is 15, but the number contributing to the primary endpoint is not reported in the registry record. The registry does not describe exclusions, withdrawals, incomplete questionnaires, or imputation. Those details are important because the endpoint estimate and its precision can depend on who contributed data and how incomplete observations were treated.
These omissions do not establish that missing data or multiplicity occurred; they mean the registry entry does not describe how such issues were addressed. With no analysis results, readers cannot assess whether the reported outcome set or participant population matches a prespecified plan.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Behavioral/Organizational Skills Intervention Plus Mobile App | 0 | 15 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Behavioral/Organizational Skills Intervention Plus Mobile App | 0 of 15 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Behavioral/Organizational Skills Intervention Plus Mobile App | 0 of 15 |
The registry safety summary lists one intervention group, titled Behavioral/Organizational Skills Intervention Plus Mobile App. It records zero participants affected by serious adverse events, zero affected by other adverse events, and zero deaths. For each category, 15 participants are listed as at risk. No serious adverse-event terms are listed.
These values describe the counts recorded in the registry. They do not provide a detailed account of event definitions, the monitoring period, collection procedures, or how events were assessed. Those details are not reported in the registry record. The at-risk values also do not establish that every participant completed the same safety follow-up.
A zero count in a registry summary should be read as no affected participants recorded in that category, not as proof that an event was impossible or that every potential event was captured. The entry does not provide enough information to evaluate the completeness of safety monitoring or to compare safety with another group. Because this was a single-group study, the safety figures are descriptive and do not constitute a comparative safety estimate.
12. What the Result Does, and Does Not, Mean
This study record is meaningful as a description of an app-development project and its planned usability assessment. It identifies a mobile application intended to augment clinician-directed behavioral and organizational skills treatment for adolescents with ADHD symptoms, and describes stakeholder input as part of prototype development. The primary measure was the SUS, intended to assess technology usability at month 3, described as 1-month post-intervention.
What the registry record does not establish is the observed usability score. Although the SUS scale range and an interpretive threshold are stated, the study’s mean score and its precision are not reported. The entry also contains no analysis results. As a result, it cannot show how participants rated the app or how consistent those ratings were.
The design limits claims about comparative effects. A single-group study without a comparator does not provide a randomized estimate against usual care, another app, or another intervention. The listed primary endpoint concerns usability, not a clinical outcome. No conclusion about changes in ADHD symptoms or other clinical outcomes follows from the endpoint definition alone.
The safety summary records zero affected participants in the listed serious-event, other-event, and death categories. Those figures are descriptive registry counts. They do not establish comparative safety, and the record does not detail event ascertainment or follow-up.
Thus, the registry supports a careful account of the study’s purpose, design, intervention schedule, planned usability endpoint, and recorded safety counts. It does not support a conclusion about the magnitude or precision of usability, clinical benefit, or comparative safety. These outcome findings are not reported in the registry record.
13. Why This Trial Matters Statistically
Development studies raise questions that are different from those addressed by comparative efficacy trials. Before an app is evaluated as part of a clinical intervention, its usability is a relevant feature to measure. The registry identifies the SUS as the primary measure and describes its interpretation, making the intended focus of this study clear.
Statistically, a well-defined outcome is only one part of an interpretable result. An observed score, information about its variability, and an account of the participants contributing data are also needed to understand what the measurement says and how precise it is. The registry record does not report the SUS result or its analysis, so the stated endpoint cannot yet be translated into an empirical estimate of usability.
The single-group structure is also important. It is consistent with an initial development focus, but it does not provide a control-based estimate of what the app adds relative to another condition. Readers should distinguish the study’s contribution as recorded—an intervention and a planned usability assessment—from questions about comparative clinical effects that this design does not answer.
Finally, transparent reporting of analysis methods, missing-data handling, and outcome results allows readers to evaluate how evidence was produced. These details are not reported in the registry record. That absence constrains interpretation without demonstrating that a particular analysis was inappropriate. The study is statistically informative as a design description, while its primary quantitative result remains unavailable in the registry entry.
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 gives limited information for evaluating the study’s methods and results. It records a single-group design, no masking, allocation listed as NA, and enrollment of 15. It does not report eligibility criteria beyond the stated condition, participant characteristics, recruitment details, or the number who completed the intervention and the month 3 assessment.
The primary SUS outcome is described, but its observed value, variability, and analysis are not reported. The registry lists four outcome measures and zero analyses, leaving the other outcomes and their results unspecified in the record. The analysis population, missing-data methods, and any handling of incomplete questionnaires are not reported. A statistical plan, sample-size justification, and interim analyses are also not reported in the registry record.
The single-group design means there is no concurrent control for comparison. The primary outcome is a usability measure, rather than a clinical endpoint, and the record does not report clinical outcome results. The intervention description specifies a schedule, but the registry does not report adherence, treatment fidelity, or the extent of app use. Further details of the stakeholder input and prototype-development process are also not reported.
Safety information is limited to summary counts. The record does not describe event definitions, collection procedures, or follow-up in detail. These limitations restrict what can be concluded from the registry entry; they do not establish that unreported procedures or data were absent from the study itself.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Development of a Mobile App for an Executive Functioning Intervention for Adolescents — NCT04018794.
- Registry record last updated 2021-11-23; status last verified 2021-11.
- Results first posted 2021-11-19.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
The registry describes a completed, single-group study developing an initial mobile app prototype to support clinician-directed behavioral and organizational skills treatment for adolescents with ADHD symptoms. Enrollment is recorded as 15. The intervention arm combined treatment with a mobile application, with 16 sessions of 20-30 minutes, twice weekly for 8 weeks. The study started on 2019-09-30, and primary completion is listed as 2020-09-01.
The primary outcome was the SUS mean score, assessed at month 3, described as 1-month post-intervention. The registry describes the scale but does not report the observed outcome value or any analysis results. Four outcome measures are listed, with zero analyses. The safety summary records zero participants affected by serious adverse events, zero affected by other adverse events, and zero deaths, with 15 at risk in each listed category. The entry does not provide a comparator, detailed analysis methods, or further safety-collection details.