Social Media And Risk-reduction Training for Infant Care Practices (SMART): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Social Media And Risk-reduction Training for Infant Care Practices (SMART) (NCT01713868), a randomized na study. The primary outcome is Adherence With Recommended Supine Sleep Position.

2. Clinical Question

3. Trial Design

SMART is a completed randomized trial with a factorial model. The registry record lists an enrollment of 1600 and describes 16 hospitals randomly assigned to four study groups. The groups combined two types of nursery education and two types of mobile health messaging: safe sleep education with breastfeeding messaging; breastfeeding education with safe sleep messaging; safe sleep education with safe sleep messaging; and breastfeeding education with breastfeeding messaging. This is a hospital-level allocation as described in the record, rather than an allocation described as occurring separately for each participant.

The record lists single masking, but does not report who was masked or how masking was maintained. It lists phase as not applicable. The sponsor is the University of Virginia. The study start is listed as 2015-03, primary completion as 2016-10, and status as completed.

The brief description frames the study as an evaluation of two complementary approaches to infant-care practices, including nursery education and mobile messaging. The primary hypothesis concerns safe sleep position and identifies potential contributions from Safe Sleep Nursery Education, Safe Sleep mHealth messaging, and their combination. The registry record does not describe the statistical model used to account for hospital-level allocation, nor does it provide a full analysis plan. Details such as eligibility criteria, participant flow, adherence to assigned interventions, and the identities of those masked are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Results analyzed at 2+ months infant age.

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 Adherence With Recommended Supine Sleep Position, measured over 6 months.

The primary endpoint is titled “Adherence With Recommended Supine Sleep Position.” It is expressed as a count of participants, and the record characterizes the outcome as binary: participants are counted according to whether they meet the adherence definition. The description frames supine sleep position as a public-health recommendation and states a hypothesis that adherence would increase with Safe Sleep Nursery Education, Safe Sleep mHealth messaging, and their combination.

The stated assessment is a survey conducted when the infant is 2-5 months of age. The population description separately says results were analyzed at 2+ months infant age, while the primary outcome timeframe is listed as 6 months. The record does not explain the relation between the 6-month timeframe and the survey age range. It also does not give the exact operational definition of adherence, such as the question wording or how responses were classified.

Using a participant count makes the endpoint interpretable as the number meeting the outcome definition in each analysis group, provided the relevant denominators are also known. The registry record does not report primary-outcome counts or denominators by group, so the endpoint's observed frequency and the size or precision of group differences cannot be determined from this record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies the allocation as randomized, the model as factorial, and the design description as four hospital-assigned groups. It also records the primary outcome as a binary participant count. These labels describe important parts of the design, but they do not provide the full statistical methods used to analyze the outcome. The registry record does not report a statistical analysis plan or the fitted model.

What does factorial mean in this design?

In general, a factorial design studies combinations of intervention components so that investigators can ask about the components as well as particular combinations. Here, the four described groups pair nursery education with mobile health messaging, using safe sleep or breastfeeding content in each. The stated primary hypothesis focuses on safe sleep education, safe sleep messaging, and their combination. To interpret those questions, readers need to know which contrasts were estimated and how the interaction between components was handled. Those details are not reported in the registry record.

Why does the hospital allocation matter?

General statistical explanation: when hospitals, rather than individuals, are randomized, participants within a hospital may share characteristics or care environments. This can make their outcomes statistically dependent. If an analysis treats all participants as entirely independent, its uncertainty estimates may be too small. Cluster-aware methods account for the grouping in the design. The record says that 16 hospitals were randomly assigned, but does not report the analysis method, any hospital-level correlation assumptions, or whether the analysis accounted for clustering.

What does a binary participant count represent?

A binary endpoint classifies each participant according to whether the outcome definition is met. Group counts can describe how many participants meet that definition, but interpretation also requires denominators and a clear outcome definition. The registry record calls the endpoint adherence with recommended supine sleep position and states that it was assessed by survey. It does not give the survey item, classification rule, group-specific results, or analysis denominators.

How should uncertainty be understood?

General statistical explanation: an estimated difference or other contrast is a summary of the observed data under a specified analysis. A confidence interval represents uncertainty around that estimate; it does not guarantee that the true value lies within the interval. A p-value, when reported, describes how compatible the data are with a specified null hypothesis under the analysis assumptions. Neither an interval nor a p-value can be interpreted without knowing the contrast, model, and analysis population. The registry record does not report these primary-outcome statistics.

What do the planning assumptions say?

The record describes planning illustrations based on a fraction of the observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. For outcomes other than time-to-event outcomes, those illustrations are expressed as participants per arm. These are planning calculations, not observed power and not the trial's observed outcome results. They do not establish that the trial was designed around those assumptions. The trial's own sample-size justification is not reported in the registry record.

General statistical explanation: sample-size planning asks what amount of information might be needed to detect a specified effect under stated assumptions. A post hoc planning illustration based on an observed effect is different from a prospective design justification, and it should not be read as the probability that the completed trial detected a true effect. Because the primary results and detailed design rationale are not reported in the registry record, the planning assumptions cannot resolve uncertainty about the actual analysis.

Overall, the available design labels establish randomization, hospital-level assignment, factorial structure, and a binary primary endpoint. The registry record does not provide enough detail to reproduce the analysis or to evaluate the precision of any primary-outcome estimate.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists eight outcome measures and eight analyses. It names secondary outcomes concerning positive or nonpositive attitudes and social norms for supine sleep and roomsharing without bedsharing. It does not explain how the listed analyses relate to each outcome, which analyses were primary or secondary beyond the named primary endpoint, or whether any multiplicity adjustment was planned or used. The strategy for handling multiple comparisons is therefore not reported in the registry record.

General statistical explanation: when many outcomes or contrasts are examined, the chance of at least one apparently unusual result can increase. Prespecified priorities and multiplicity procedures can help readers distinguish confirmatory questions from exploratory ones. Without an analysis plan or reported adjustment method, the strength of evidence across multiple tests cannot be assessed.

The registry record does not report how missing survey responses were handled, whether participants were excluded from particular analyses, or whether any imputation or sensitivity analysis was used. It also does not describe the analysis population, such as whether results were based on all participants according to assigned group or on a subset with completed surveys. The listed enrollment does not establish how many participants contributed to each endpoint. These omissions limit assessment of the risk of bias from missingness and of how closely the analyzed population followed the randomized allocation.

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 adverse-event record lists four groups. In each group, 400 participants are listed as at risk for serious events and 400 as at risk for other events; the recorded affected counts are 0 for serious events and 0 for other events, and deaths are listed as 0. No serious-event terms are listed.

These figures describe what was entered in the registry record; they do not establish that no events occurred outside the recorded categories or observation period. The record does not provide further information about event collection, monitoring, reporting completeness, or the time period for these safety counts. Zero recorded events also do not establish that the intervention combinations are safe or unsafe. They should be read as registry-reported counts, with the reporting limitations kept in view.

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

The SMART registry record describes a randomized, factorial study of nursery education and mobile messaging for infant-care practices, with a primary question about adherence to recommended supine sleep position. It also states hypotheses concerning safe sleep education and messaging. Those design details explain what the investigators intended to study, but they do not reveal what the primary outcome results were.

The record does not report the primary endpoint counts, group-specific denominators, effect estimates, confidence intervals, or significance tests. Consequently, it cannot establish whether adherence differed across the four intervention combinations, how large any difference was, or how precisely it was estimated. The absence of reported results is not evidence that there was no difference. Nor does the stated hypothesis show that a difference was observed.

The combination structure also matters. Even if a contrast between two groups were available, its interpretation would depend on which intervention components differed and on the analysis used. The registry record does not report the exact primary contrasts or the treatment of component interactions. It therefore does not support a component-specific conclusion.

General statistical interpretation: a trial result is an estimate in a defined population, measured with a particular outcome definition and analyzed under stated assumptions. It is not automatically a statement about all settings or populations. In this case, the population details and the analysis methods are not fully reported in the registry record, and the primary results are absent. The record can be used to understand the trial's registered question and broad structure, but not to judge the magnitude, precision, or practical importance of its primary outcome findings.

13. Why This Trial Matters Statistically

Statistically, SMART raises questions that are important for interpreting intervention studies: how to separate the contribution of education from mobile messaging, whether combining components changes their effects, and how to account for randomization by hospital. The four-arm factorial arrangement is relevant because each package combines content in a different way, while the primary hypothesis specifically refers to safe sleep education and messaging.

The cluster allocation is also central. General statistical explanation: randomizing hospitals can be useful when an intervention is delivered through a hospital setting, but it changes the structure of the data. Outcomes within a hospital may be correlated, so analysis and uncertainty estimates need to reflect the allocation unit. The registry record confirms hospital-level assignment but does not describe the analysis used to handle clustering.

The endpoint is a participant-level binary count assessed by survey, with different age descriptions in the outcome timeframe and population fields. Clear reporting of the survey definition, analysis population, missing data, denominators, and group-specific estimates would help readers judge what the results mean and how precise they are. Those primary results and methods are not reported in the registry record.

The record therefore offers useful design context but leaves the central statistical questions unanswered. Its significance for readers is partly methodological: it illustrates why factorial contrasts, clustered allocation, outcome definitions, and complete reporting all matter when evaluating a behavioral intervention trial. Without posted primary findings, no inference about the direction or size of the outcome can be drawn.

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 this trial record is that it does not report results for the primary outcome. There are no adherence counts by group, denominators, effect estimates, confidence intervals, or tests. The record therefore cannot support an assessment of the outcome's direction, magnitude, or precision.

Several details needed to interpret the endpoint are also absent. The record does not provide the exact survey question or adherence classification rule. It lists a 6-month timeframe, describes a survey at infant age 2-5 months, and says results were analyzed at 2+ months infant age, without explaining how these timing descriptions fit together.

The record describes random assignment of hospitals, but does not report the statistical model or how clustering was handled. It does not identify the exact contrasts used for the factorial questions or explain how component interactions were analyzed. Masking is listed as single, but the masked parties are not identified.

Information about participant flow, group-specific analysis denominators, missing responses, exclusions, and the analysis population is not reported in the registry record. The multiplicity approach for the listed outcome measures and analyses is also not reported. These gaps prevent readers from evaluating potential effects of missing data, the precision of the estimates, and the interpretation of multiple comparisons. The listed safety counts likewise lack detail about event collection and reporting.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Social Media And Risk-reduction Training for Infant Care Practices (SMART) — NCT01713868.
• Registry record last updated 2019-01-11; status last verified 2019-01.
• Results first posted 2019-01-03.
• 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

SMART is listed as a completed, randomized, factorial trial sponsored by the University of Virginia. The record describes four hospital-assigned combinations of nursery education and mobile health messaging, with 16 hospitals and an enrollment of 1600. Single masking is listed, but the masked parties are not identified.

The primary outcome is adherence with recommended supine sleep position, recorded as a participant count and assessed by survey. The record describes the survey age as 2-5 months, gives a 6-month timeframe, and states that results were analyzed at 2+ months infant age. The primary hypothesis concerns safe sleep education, safe sleep messaging, and their combination.

Primary-outcome results and key analysis details are not reported in the registry record. The adverse-event entries list 0 serious events, 0 other events, and 0 deaths in each group. These safety entries should be interpreted as registry-reported counts, not as a complete assessment of safety.