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 Increasing Physical Activity Among Sedentary Older Adults:What, Where, When, and With Whom (NCT03124537), a randomized na study. The primary outcome is Number of Steps Walked.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03124537 |
| Phase | NA |
| Condition | Sedentary Lifestyle, Self Efficacy, Control Locus |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 86 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Brandeis University |
| Results posted | Yes |
2. Clinical Question
Population
Sedentary older adults participating in the study. The registry record lists an enrollment of 86. It says that participants who dropped out or experienced an app crash were excluded, while also describing the analyses as intent to treat; how those statements were reconciled is not reported in the registry record.
Intervention
The experimental app condition set step goals and included schedule, map, and social components for 1 month. The study goal was to support planning where, when, and with whom to walk.
Comparator
The control app condition included an accelerometer program to set step goals and count and record steps for 1 month. It did not include the schedule, map, and social components described for the experimental condition.
Primary question
The registry describes a comparison of the number of steps walked, measured as average daily steps from phone-app records. The stated aim was to examine whether the experimental app condition changed daily steps relative to the control condition. The registry record does not report the estimated difference, its uncertainty, or a statistical test result, so the direction and precision of any between-condition difference cannot be described.
3. Trial Design
This was a randomized, single-masked, parallel-group study of behavioral app conditions. The registry lists 86 participants as enrolled. The adverse-event record lists 41 participants at risk in the App Control Condition and 45 in the App Experimental Condition. The registry record does not identify who was masked, describe the randomization sequence or allocation concealment, or report whether the assigned groups were balanced on baseline characteristics.
The control condition used an app with an accelerometer program for setting step goals and counting and recording steps. The experimental condition used step goals plus scheduling, mapping, and social components. Both descriptions specify a 1-month period. The study aimed to develop and test a smartphone app program to help sedentary older adults increase daily steps by planning walks, and also examined self-efficacy and social integration or support.
The primary outcome was number of steps walked, expressed as average daily steps. Steps were recorded daily through the phone app, with weekly step averages described as the outcome data. Secondary outcomes included exercise self-efficacy, exercise control beliefs, social contact through the app, daily mood and energy, and self-reported vigorous, moderate, and light physical activity. The record lists 8 outcome measures and 16 analyses. Their exact analysis-by-outcome mapping is not reported in the registry record.
The study is marked completed. It is listed as not having a phase. The registry dates include a start date of 2017-10-16 and a primary completion date of 2019-03-29. These design details identify the comparison and the intended measurements, but do not establish the size or statistical certainty of any treatment contrast.
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
| Stage | App Control Condition | App Experimental Condition |
|---|---|---|
| STARTED | 41 | 45 |
| COMPLETED | 31 | 32 |
| NOT COMPLETED | 10 | 13 |
Reasons for not completing this period:
| Reason | App Control Condition | App Experimental Condition |
|---|---|---|
| Lost to Follow-up | 3 | 5 |
| App Crash, Incomplete Data | 7 | 8 |
Analysis population for the primary outcome, as defined in the registry: Participants were excluded if they dropped out of the study or experienced the app crash. Analyses were conducted using an intent to treat population. Daily step averages less than 500 steps were classified as a missing day of data. Weekly step averages were only calculated if there were 4 or more days of valid data.
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 | App Control Condition | App Experimental Condition | Total |
|---|---|---|---|---|
| Participants analysed | 31 | 32 | 63 | |
| Age, Continuous | years | 64.71 (SD 6.30) | 63.63 (SD 7.89) | 64.16 (SD 7.12) |
| Sex: Female, Male: Female | Participants | 21 | 20 | 41 |
| Sex: Female, Male: Male | Participants | 10 | 12 | 22 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 1 | 0 | 1 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 30 | 32 | 62 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 1 | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 3 | 3 | 6 |
| Race (NIH/OMB): White | Participants | 28 | 28 | 56 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Region of Enrollment: United States | participants | 31 | 32 | 63 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Steps Walked, measured over Daily for one month.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | Average Daily Steps |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the number of steps walked, measured as average daily steps. The registry describes daily step counts recorded by the phone app and weekly averages of those counts during the month of app use. Step counts are a continuous measure of activity: they retain gradations in recorded walking rather than reducing the outcome to a yes-or-no category.
As a general statistical matter, a continuous activity measure can capture variation between participants and changes over time. An average can provide a compact description of recorded activity, while the underlying day-to-day values may vary. The endpoint is relevant to the stated study aim because the app program was intended to help participants increase daily steps through planning walks. The registry record does not report the baseline and follow-up summaries, the estimated between-condition contrast, or its confidence interval, so the degree of change and its precision cannot be assessed from the record details.
The outcome rules matter to interpretation. Daily averages below 500 steps were classified as missing days. Weekly averages were calculated only when there were 4 or more d of data. These rules affect which observations contribute to a weekly average and make the handling of incomplete activity recording important. The registry record does not explain whether other approaches to missing step data were used or how the endpoint was summarized in the reported analysis.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The study’s primary question concerns a comparison between the experimental app condition and the control app condition on average daily steps. The registry describes the endpoint and measurement period, but the registry record does not report group outcome summaries, an estimated contrast, a confidence interval, or a p-value. As a result, the registry entries do not establish whether the groups’ recorded step counts differed, how large any difference was, or how precisely it was estimated. No conclusion about the direction or magnitude of the primary outcome can be drawn from the design description alone.
A confidence interval, as a general statistical concept, indicates a range of values compatible with the data and the analysis assumptions. It helps readers judge precision: a narrower interval indicates greater precision than a wider interval. Without an interval or other measure of uncertainty, the statistical precision of the primary comparison cannot be assessed. A p-value, also as a general concept, measures how compatible observed data are with a specified null model; it does not by itself measure effect size, practical importance, or the probability that a treatment works. No such primary comparison result is reported in the registry record.
The registry lists 8 outcome measures and 16 analyses, and the primary outcome has several categories or time points that were not reduced to a single comparison. This makes it especially important to know which outcome contrast was designated as primary, which time points were analyzed, and whether the analysis accounted for multiple comparisons. The exact multiplicity approach and the full mapping of analyses are not reported in the registry record. Statistical evidence from multiple outcomes or time points should therefore not be treated as if it came from a single prespecified test unless that plan is documented.
The enrollment count and arm counts describe the study size, not the result’s precision by themselves. Precision also depends on variability in step counts, the analysis population, completeness of measurement, and the statistical model. Those outcome and model details are not reported in the registry record. The planning assumptions state a two-sided significance level of 0.05, equal allocation, and a normal approximation for sample-size illustrations based on fractions of an observed effect. These are planning conditions, not evidence that a particular effect was observed or that a specified power was achieved. The observed effect used for those illustrations is not reported in the registry record.
Accordingly, the information supports a description of the trial question, app conditions, outcome definitions, and selected data rules. It does not support a conclusion about whether the experimental condition changed daily steps relative to control. Interpreting the trial’s results requires the group estimates and uncertainty measures, along with a clear account of the analysis population and handling of missing data.
9. Statistical Methods Explained
The registry identifies a randomized, single-masked, parallel-group design. In a randomized study, assignment is intended to make the groups comparable on average with respect to factors that could affect the outcome. Randomization does not guarantee identical groups, especially in a study of this size, and it does not eliminate the need to report baseline characteristics and follow-up data. The sequence-generation method, allocation concealment, and identity of the masked participants are not reported in the registry record. Those details matter for evaluating how assignment was implemented and whether knowledge of assignment could have influenced behavior, measurement, or analysis.
What does the mean represent?
The primary measure is average daily steps, a continuous outcome. A group mean describes the center of the recorded step counts for that group under the stated analysis. The registry lists standard deviation as the measure of dispersion. As a general statistical explanation, the standard deviation describes how spread out observations are around the mean; it is not the same as the uncertainty in the estimated mean. Uncertainty in a group contrast depends on the amount of data and variability, among other features of the analysis.
The outcome description refers both to daily measurements and weekly averages. Repeated measurements from the same participant are generally related, rather than independent. A statistical analysis of daily or weekly observations may need to account for that within-participant relationship. The specific model, covariance assumptions, and method for producing the reported primary comparison are not reported in the registry record. Without those details, the analysis cannot be independently characterized beyond the stated outcome and design.
How should uncertainty be read?
As a general concept, a confidence interval presents uncertainty around an estimated contrast on the outcome’s scale. For a between-condition estimate, the interval helps distinguish a result that is estimated precisely from one that remains compatible with a broad range of effects. The interval should be read together with the estimate and the outcome units. A p-value addresses compatibility with a null hypothesis under the chosen model, but does not describe the size or importance of a difference. The registry record does not report the primary estimate, confidence interval, or p-value.
The sample-size assumptions describe planning illustrations based on fractions of an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. These are stated assumptions for illustrative planning, not the trial’s documented design justification. The registry record does not report the protocol’s sample-size justification, the effect estimate used in those illustrations, or an interim-analysis plan. A planning calculation should not be interpreted as observed power: it does not establish the probability that the completed study detected its actual effect.
Why can variability affect the analysis?
As a general statistical explanation, over-dispersion occurs when variation in the data is greater than a model assumes. If a model understates variability, uncertainty intervals may be too narrow and tests may appear more decisive than warranted. Activity counts can have uneven distributions across people and days, but whether over-dispersion was assessed or relevant to the fitted analysis is not reported in the registry record. No specific distributional assumption for the primary endpoint is stated in the record details.
Daily step values also depend on device recording and participants’ patterns of use. The registry states that values below 500 steps were treated as missing days, and that a weekly average required 4 or more d of recorded data. These are rules for classifying available measurements; they do not, on their own, show whether missingness was related to activity level, app use, or study group. The statistical consequences depend on why data are missing and how the analysis handles them. The registry record does not report a missing-data model, imputation procedure, or sensitivity analysis.
What does the analysis population imply?
The primary outcome description says participants were excluded if they dropped out or experienced an app crash, and also says analyses used an intent-to-treat population. In general, an intent-to-treat analysis aims to retain participants in the groups to which they were randomized, regardless of adherence or treatment received. Excluding participants after randomization may differ from that principle, depending on the stated population and exact implementation. The registry wording does not explain how exclusions were applied, whether all randomized participants were included, or how app crashes and dropouts were accounted for. The analysis population therefore cannot be determined more precisely from the registry record.
The registry’s listed 8 outcome measures and 16 analyses also make the statistical plan relevant. As a general concept, multiplicity arises when several outcomes, time points, or comparisons are tested. Conducting multiple tests can increase the chance of obtaining at least one apparently unusual result under a null model. Methods such as a prespecified hierarchy or adjustment can address particular multiplicity concerns, but no such approach is reported in the registry record. The record also does not identify a complete hierarchy of outcomes or clarify which comparisons were prespecified.
These methodological concepts describe what readers would need to evaluate estimates; they are not claims about analyses that were conducted. The registry record provides some design and outcome rules, but does not report enough statistical-plan detail to determine the model, inferential procedure, missing-data approach, multiplicity control, or robustness checks for the primary comparison.
10. Multiplicity, Missing Data and Analysis Populations
Multiplicity is relevant because the registry lists 8 outcome measures and 16 analyses, and the primary outcome has several categories or time points. When several outcomes or contrasts are examined, the chance of finding an apparently notable result by chance can increase. As a general statistical principle, interpretation is clearer when the primary comparison and analysis hierarchy are specified in advance, and when any adjustment or other multiplicity strategy is described. The registry record does not report whether adjustments were used, which analyses were prespecified, or how the 16 analyses map to outcomes and time points.
Missingness also affects this endpoint. The record states that daily step averages below 500 were classified as missing days and that weekly averages were calculated only when there were 4 or more d of data. It also says participants who dropped out or experienced an app crash were excluded, while describing the analyses as intent to treat. The registry record does not explain how those statements were reconciled, how many observations were missing, whether missingness differed by group, or whether any imputation or sensitivity analysis was performed.
As a general concept, an intent-to-treat analysis retains participants according to randomized assignment, while missing outcomes still require a defined approach. The label alone does not specify how incomplete daily records are handled. Because the implementation and analysis population are not reported in detail, the potential influence of exclusions and missing step counts on the comparison cannot be judged from the registry record.
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 |
|---|---|---|---|
| App Control Condition | 0 | 41 | 0.0% |
| App Experimental Condition | 0 | 45 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| App Control Condition | 0 of 41 |
| App Experimental Condition | 0 of 45 |
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 |
|---|---|
| App Control Condition | 0 of 41 |
| App Experimental Condition | 0 of 45 |
The serious adverse event record lists 0 serious adverse events among 41 participants at risk in the App Control Condition and 0 among 45 participants at risk in the App Experimental Condition. The record also lists 0 deaths in each condition. No serious adverse event terms are listed.
These figures describe events recorded during the study and the numbers of participants at risk in each group. A zero count means that no serious adverse events were recorded in the registry’s serious-event summary; it does not establish that no adverse events of any kind occurred. The serious-event figures do not provide information about non-serious events, event timing, duration, relatedness to the app, or differences in reporting between groups. Those details are not reported in the registry record.
As a general statistical point, a zero observed count does not prove that the underlying risk is zero. The interpretation depends on the amount and duration of observation and the completeness of event collection, which cannot be fully assessed from the serious-event counts alone. These data describe safety reporting; they do not determine the primary step-count outcome or the statistical precision of its comparison.
12. What the Result Does, and Does Not, Mean
The registry record defines a randomized comparison between a step-goal and step-recording app condition and an app condition that added scheduling, mapping, and social components. It identifies average daily steps as the primary outcome and describes how daily records were converted into weekly averages. It also lists secondary measures related to exercise beliefs, app-based social contact, mood, energy, and self-reported activity.
Those details establish the study’s intended question, but they are not outcome evidence. The registry record does not report the primary group estimates, the between-condition contrast, a confidence interval, or a test result. It therefore does not establish whether the experimental condition was associated with higher, lower, or similar average daily steps, nor does it quantify the precision of a possible difference. The same limitation applies to the secondary outcomes: their inclusion in the record does not establish the direction or size of their results.
As a general interpretive distinction, statistical evidence and practical importance are not interchangeable. A precise estimate may still be small in practical terms, while an imprecise estimate may leave uncertainty about effects that could matter. Evaluating either requires an estimate, uncertainty measure, and context for the outcome. None of those outcome results is reported in the registry record.
The sample-size assumptions are planning illustrations based on fractions of an observed effect and specified statistical conditions. They are not observed outcomes and should not be read as evidence that a particular effect was achieved or detected. The registry record does not report the observed effect used for the illustrations or the trial’s own sample-size justification.
The appropriate conclusion is limited: this completed study tested two app conditions in sedentary older adults, with daily steps as the primary measure, but the record details do not permit a statistical conclusion about the primary comparison. More complete outcome estimates and analysis details would be needed to assess effect direction, magnitude, uncertainty, and sensitivity to missing data or multiple analyses.
13. Why This Trial Matters Statistically
This trial is statistically notable for measuring activity repeatedly through a phone app while comparing two behavioral app conditions. The primary endpoint is not a single self-report at the end of the study: the registry describes daily step records and weekly averages during a month. Repeated measurement can describe variation over time, but it also raises analysis questions about correlated observations, incomplete days, and how a participant-level summary is formed.
The registry makes some data-processing rules explicit. Daily averages below 500 steps were treated as missing, and a weekly average required 4 or more d of data. Such rules can affect which observed days contribute to a summary. Their consequences depend on the frequency and reasons for missing data, which are not reported in the registry record. The stated exclusion of dropouts and app crashes, alongside the intent-to-treat description, further makes the exact analysis population important to understand.
The record also lists multiple outcome measures and analyses. This illustrates why a clearly specified primary contrast and transparent multiplicity handling matter: the interpretation of a result can depend on which outcomes and time points were selected and how many comparisons were considered. The multiplicity plan is not reported in the registry record.
Finally, the registry describes planning assumptions for sample-size illustrations but does not report the trial’s own justification or the outcome estimates needed to judge precision. This distinction matters because planned sample size, observed effect, and uncertainty in the completed analysis answer different statistical questions. The design and measurement details make the intended comparison understandable, while the missing results and analysis specifications limit what can be concluded about its evidence.
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 principal limitation for statistical interpretation is that the registry record does not report the primary outcome summaries or comparison estimate. Without the estimated between-condition difference and a measure of uncertainty, effect direction, magnitude, and precision cannot be assessed. The same absence of reported estimates limits interpretation of the secondary outcomes.
The analysis population is not fully clear from the registry description. It says that participants who dropped out or experienced an app crash were excluded, and also describes the analyses as intent to treat. The registry record does not explain how exclusions were handled, whether all randomized participants were represented in the analysis, or how those definitions relate to the stated analysis population.
The endpoint rules identify missing days and a minimum number of days for a weekly average, but the number and pattern of missing measurements are not reported. The reasons for missingness, handling of incomplete weeks, and use of any imputation or sensitivity analyses are also not reported in the registry record. These omissions prevent assessment of whether missingness could have influenced group comparisons.
The statistical model and inferential procedure are not specified in the registry record. In particular, the record details do not explain how repeated measurements were modeled, how variability was estimated, or how outcome comparisons across time points were selected. Although the record lists 8 outcome measures and 16 analyses, the analysis mapping and any multiplicity approach are not reported.
Further design details—including who was masked, the randomization procedure, allocation concealment, and the trial’s sample-size justification—are not reported in the registry record. These limitations concern reporting available for interpretation; they do not establish that the procedures were absent or improperly conducted.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Increasing Physical Activity Among Sedentary Older Adults:What, Where, When, and With Whom — NCT03124537.
- Registry record last updated 2020-10-20; status last verified 2020-10.
- Results first posted 2020-10-20.
- 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.
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18. Record Summary
NCT03124537 is a completed randomized, single-masked, parallel-group behavioral study sponsored by Brandeis University. It enrolled 86 sedentary older adults and compared an app control condition with an app experimental condition. The control app set step goals and counted and recorded steps; the experimental condition added scheduling, mapping, and social components. Both conditions were described for 1 month.
The primary outcome was number of steps walked, expressed as average daily steps and based on phone-app records. The registry describes daily and weekly summaries, classifies daily averages below 500 steps as missing, and requires 4 or more d of data to calculate a weekly average. The record lists 8 outcome measures and 16 analyses.
The serious adverse event summary lists 0 events and 0 deaths in each group. The primary outcome estimate, its uncertainty, the detailed analysis plan, and the handling of the stated exclusions alongside the intent-to-treat description are not reported in the registry record.