Patient Centered Postpartum Contraception App: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Patient Centered Postpartum Contraception App (NCT03402217), a registered phase not stated study. The primary outcome is Feasibility of Application.

2. Clinical Question

3. Trial Design

The registry record describes a completed, single-arm behavioral intervention study titled Patient Centered Postpartum Contraception App. The sponsor was the University of Chicago. The study start date is listed as 2018-05-18, and the primary completion date as 2019-01-07. Enrollment was 20. The condition listed is Contraceptive Usage.

The intervention was a smartphone application designed to inform pregnant women ages 15-25 about contraception options. The stated purpose was to evaluate usability, feasibility, and acceptability. The primary outcome was measured immediately after the intervention. No randomized allocation or control group is described; allocation is not stated. A comparison between the app and another approach is therefore not part of the design described in the registry.

The registry lists secondary outcomes concerning prior method use, number of pregnancies including the current pregnancy, contraception knowledge, patient activation, information, motivation and behavioral skills, number of children, number of induced abortions, and number of miscarriages. The registry also records 10 outcome measures and 4 analyses. Details about the analysis populations, the timing of secondary assessments, and the methods used to analyze those outcomes are not reported in the registry record.

One individual of the 20 total participants completed the pre-test and received the intervention but did not complete the post-test. The registry does not state how this missing post-test was handled in the analysis or how many participants contributed to each reported measure. It also does not report recruitment procedures, study sites, app-use instructions, or the duration of exposure. The record’s completed status describes the study status, but does not by itself supply the missing endpoint results or analysis details.

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 enrolled participants were assigned to the single intervention group.

Overall Study

Analysis population for the primary outcome, as defined in the registry: One individual of the 20 total participants completed the pre-test and received the intervention but did not complete the post-test.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Feasibility of Application, measured over Immediately post intervention.

The primary endpoint is titled Feasibility of Application. It concerns participants’ ratings of the application’s feasibility, acceptability, and usability, with the mean of each item intended for reporting immediately after the intervention. This kind of endpoint can help describe whether participants found a digital tool usable and acceptable in the context in which it was tested. It addresses participants’ experiences with the app, rather than a clinical outcome or a comparison of outcomes between groups.

Each item has a possible score from 1 to 5. The registry defines 1 as strongly disagree and 5 as strongly agree. For most items, higher scores indicate a better result. The description identifies exceptions: “I found the app too complex to understand,” “I think I would need tech support to use this app,” “I thought there was too much inconsistency in app,” “I found the app cumbersome to use,” and “I needed to learn a lot before I could get going.” For these negatively worded items, lower scores indicate a better result.

Because the direction differs for those items, their meaning must be read from the item wording rather than inferred from the scale value alone. The registry gives the scale and scoring direction but does not report the item-level means or standard deviations. It also does not report a combined score or explain whether any items were combined. Consequently, the endpoint’s measurement plan is described, but the observed ratings and their precision cannot be evaluated from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes the primary outcome as continuous and specifies a mean and standard deviation for each item. In general, a mean is a summary of the central level of responses, while a standard deviation describes how dispersed individual responses are around that mean. These summaries answer different questions: a similar average can accompany either tightly clustered or widely varying responses. The registry record does not report the actual means or standard deviations for the application items.

The response options run from 1 to 5, with verbal anchors of strongly disagree and strongly agree. This is an ordered rating scale: the response categories have an order, but the description does not establish that the distance between adjacent categories is identical in participants’ interpretation. Reporting a mean treats the numeric scores as suitable for an average summary. That is the summary approach specified in the registry. The item wording remains important because the scoring direction is reversed for the negatively phrased usability statements listed in the endpoint description.

As a general statistical concept, a standard deviation helps describe participant-to-participant variation, but it is not a measure of how precisely the mean has been estimated. A confidence interval is a range of values compatible with the observed data under a stated statistical procedure; its width reflects uncertainty in the estimate. Confidence intervals for the endpoint are not reported in the registry record. Neither are p-values or a specific inferential test for the primary outcome. The record therefore supports describing the planned summaries, but not reconstructing an inferential analysis.

The study is described as a single-arm intervention, and allocation is not stated. That design does not provide a randomized control comparison. A within-group mean after the intervention, if reported, would describe the observed ratings in the group assessed. It would not by itself estimate a contrast with usual care or another intervention. General statistical interpretation should keep this distinction clear: a descriptive summary is not a between-group treatment effect.

The record lists a planning illustration based on the observed effect and states its assumptions: a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a stated fraction of the observed effect. This is a hypothetical planning framework, not a description of the single-arm study design. Such an illustration is not the trial’s original sample-size justification and is not observed power. The registry does not report the trial’s own sample-size justification. The numerical results needed to interpret an observed-effect-based illustration are also not reported in the registry record.

In general, power is a property of a specified design, assumed effect, variability, significance level, and sample size. It is not a probability that a particular finding is true, and a planning calculation does not describe the certainty of an observed result. When planning assumptions use an effect estimated from the same study, the resulting illustration should be treated as exploratory rather than as an independent validation of that effect. The record does not describe a prospective power calculation, the assumed variability for the primary endpoint, or an intended detectable difference.

Dispersion also matters in planning and interpretation. In general, if responses vary more across participants, the average is estimated less precisely for a given amount of data. If responses are concentrated near one end of a bounded rating scale, the data may not behave like an unbounded continuous measurement. These are general considerations, not reported features of the participants’ scores in this study. The observed distribution, item-level variation, and any assessment of model assumptions are not reported in the registry record.

Over-dispersion is a general concern when a statistical model assumes less variability than is present in the data; standard errors can then be too small and inferential conclusions too confident. The registry does not report a model for the primary endpoint, so it is not possible to assess whether over-dispersion was relevant or how it was handled. For item-level ratings, a statistical analysis might also account for the ordered nature of responses, but the registry does not identify such an analysis. No particular method should be attributed to the investigators without a report of it.

The registry lists 4 analyses, but does not identify the primary analysis procedure, covariate adjustment, subgroup analysis, interim analysis, or multiplicity strategy. It does not state whether analyses were prespecified or whether any recalculations were conducted. General principles cannot fill those gaps: a reader should distinguish what the record documents from methods that might be reasonable in another study. In this case, the documented primary summary is the mean of each item, with standard deviation as the dispersion measure; further statistical procedures are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists multiple outcome measures, including the primary feasibility endpoint and secondary measures concerning contraceptive history, knowledge, patient activation, information, motivation and behavioral skills, and reproductive history. When several outcomes are examined, general statistical practice recognizes a multiplicity issue: the more separate inferences considered, the greater the chance that at least one may appear noteworthy by chance alone. Whether and how to address that issue depends on the analysis plan and the role of each outcome. A multiplicity adjustment or hierarchy of outcomes is not reported in the registry record.

The record reports 4 analyses, but does not describe which outcomes or comparisons each analysis covers. It does not state whether there were interim analyses, whether outcome analyses were prespecified, or how any decisions about statistical significance were made. Those details are not reported in the registry record, so no particular testing strategy should be assumed.

Missing data are relevant to the primary endpoint: one individual completed the pre-test and received the intervention but did not complete the post-test. The reason is not reported, nor is any method for handling the absent post-test response. The registry does not state whether the analysis used available observations, imputed missing values, or applied another approach. It also does not report the number of participants included in each outcome analysis. The enrollment count should not be treated as the analysis denominator for every measure.

Analysis populations, such as an intention-to-treat population or a per-protocol population, are not reported in the registry record. It is therefore unclear which participants were included in each analysis and how deviations or incomplete assessments were addressed. In general, missing-data methods rely on assumptions about why data are missing; different assumptions can lead to different estimates. Without the analysis description and endpoint results, the impact of the missing post-test cannot be assessed.

11. 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 a single-arm intervention group with 20 participants at risk for serious adverse events and 20 at risk for other adverse events. It records 0 serious adverse events, 0 other adverse events, and 0 deaths. No serious adverse event terms are listed. These figures are descriptive counts for the group recorded in the registry.

A count of zero means that no event of that category was recorded in this group for the registry’s safety reporting. It does not prove that an event is impossible, and it does not establish how the app compares with another approach. In general, rare events are difficult to characterize in a small study, and the absence of recorded events does not provide a precise estimate of the frequency of uncommon harms. The registry does not report additional safety-monitoring methods or detail the period over which adverse events were collected.

Because the study has no described comparator, the safety figures cannot be used to estimate a relative difference between groups. They also should not be conflated with the missing post-test response, which is an assessment-completion issue rather than an adverse event in the registry’s account. The safety record is limited to the counts and at-risk totals reported.

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

This study addresses an early, practical question: how participants rate a smartphone application intended to inform pregnant women about contraception options. The registry identifies feasibility, acceptability, and usability as its focus and specifies item-level mean scores immediately after the intervention. Such ratings can be useful in describing participant experience and identifying aspects of an application that may merit further evaluation.

The record does not report the numerical results for the primary items. It is therefore not possible to say what the participants’ ratings were, how responses varied, or how precisely an average rating was estimated. The score anchors and scoring directions explain how future or posted values should be read, but they do not reveal the observed values themselves. The record’s completed status does not supply the missing endpoint results.

The study is single-arm and does not describe a randomized comparison. Its design, as recorded, cannot establish how ratings would differ under a comparator condition. Even if item means were available, they would summarize responses among the participants who contributed data; they would not by themselves demonstrate that the app caused a change in knowledge, behavior, or contraceptive use. The registry does not report comparative estimates for such outcomes.

The enrollment was 20, and the primary endpoint description notes one participant who did not complete the post-test. The record does not explain how that missing assessment was handled. This limits understanding of the population represented by any post-intervention summary, especially because the item results and analysis denominator are not reported.

The recorded absence of serious adverse events, other adverse events, and deaths is a descriptive safety observation, not proof that adverse events cannot occur. It does not provide a comparison with other options. The appropriate interpretation is bounded by the record: it describes a completed single-arm app study, its planned experience-focused endpoint, and safety counts, but does not report the item results or enough analysis information to draw broader conclusions about comparative effects.

13. Why This Trial Matters Statistically

Feasibility studies ask whether an intervention can be delivered and assessed in a way that supports further evaluation. For a digital tool, participant ratings of usability and acceptability can reveal practical barriers that clinical outcome measures alone may not capture. The endpoint in this study is explicitly focused on those experience-related questions rather than on a clinical comparison.

Statistically, the distinction between descriptive and comparative evidence is central. A single-arm set of ratings can characterize responses among participants who completed the assessment, but it cannot isolate the effect of the app from other influences. Without a control group, ratings are not a randomized contrast. This remains true regardless of whether a summary is a mean, a standard deviation, or another descriptive measure.

The record also illustrates why reporting the numerical endpoint results and analysis population matters. A stated scale and scoring direction explain the measurement, but readers need the observed values to understand the responses. Knowing that one participant did not complete the post-test also makes the handling of missing data relevant. Without the analysis denominator and method, it is not possible to determine exactly whose responses inform the endpoint.

Finally, feasibility findings and planning calculations serve different purposes. A sample-size illustration based on an observed effect can help explore hypothetical future designs, but it does not establish the study’s original design rationale or its achieved power. The record says that the illustration assumes a two-arm allocation even though the study itself is described as single-arm. Keeping those roles separate helps prevent a planning scenario from being mistaken for a randomized trial result.

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 primary limitation for interpreting the endpoint is that its item-level means and standard deviations are not reported in the registry record. The scale, timing, and scoring directions are described, but no numerical ratings are available for assessing participants’ views. As a result, the stated purpose of evaluating feasibility, acceptability, and usability cannot be evaluated from the primary outcome results in this record.

The study is described as a single-arm intervention, with no comparator group and no stated allocation. This prevents a like-for-like comparison and limits conclusions to the experience captured within the study group. The registry does not report app-use details, recruitment procedures, participant characteristics beyond the intended age range, or study setting, which further constrains contextual interpretation.

One individual completed the pre-test and received the intervention but did not complete the post-test. The reason for missingness, the analysis denominator, and the method used to handle the missing assessment are not reported. This leaves uncertainty about how the incomplete post-test affected the endpoint analysis. Analysis populations and any prespecified statistical plan are also not reported.

The registry lists secondary outcomes and 4 analyses but does not provide the corresponding analysis methods or results in the information recorded. A multiplicity strategy, interim analyses, sample-size justification, and inferential procedures are not reported in the registry record. The planning illustration uses a hypothetical two-arm framework and is not the design described for the study. Finally, the safety counts are descriptive and do not provide a comparative safety estimate.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Patient Centered Postpartum Contraception App — NCT03402217.
• Registry record last updated 2024-05-03; status last verified 2024-05.
• Results first posted 2024-05-03.
• 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.

18. Record Summary

NCT03402217 is a completed, single-arm study sponsored by the University of Chicago, titled Patient Centered Postpartum Contraception App. The registry lists enrollment of 20, a start date of 2018-05-18, and a primary completion date of 2019-01-07. The behavioral intervention was a smartphone application designed to inform pregnant women ages 15-25 about contraception options.

The primary outcome, Feasibility of Application, was intended to summarize item ratings immediately after the intervention, using means and standard deviations on a 1-to-5 response scale. One individual completed the pre-test and received the intervention but did not complete the post-test. The primary item results and missing-data handling are not reported in the registry record.

The registry records 0 serious adverse events, 0 other adverse events, and 0 deaths among 20 participants at risk in the intervention group. It describes no randomized comparator. The record also lists secondary outcomes and 4 analyses, but the analysis methods and secondary numerical results are not reported.