A Mobile-health Pilot Experiment Targeting Mothers With Newborns in Rural Areas of San Juan Sacatepequez, Guatemala: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Mobile-health Pilot Experiment Targeting Mothers With Newborns in Rural Areas of San Juan Sacatepequez, Guatemala (NCT02263118), a randomized na study. The primary outcome is Number of Participants With Changes in Knowledge.

2. Clinical Question

The trial asked whether mobile-health approaches promoting recommended breastfeeding practices could transmit the exclusive-breastfeeding message to participating mothers and improve infants’ weight evolution. The primary outcome focused on changes in mothers’ knowledge over the experiment, rather than on a single endpoint such as message receipt. The registry described transitions between incorrect and correct knowledge from the beginning to the end of the study.

The research question therefore has several related parts: learning the message, forgetting it, remaining unaware, and remembering it. These transitions distinguish initial knowledge from knowledge at the end of follow-up. They also make the outcome more informative than an endpoint that only records whether a participant was correct at the final assessment. However, without the transition counts or a prespecified contrast, the registry record does not establish how the groups compared on these patterns.

3. Trial Design

The registry describes a randomized, double-masked, parallel-group study and labels its phase as NA. Its listed enrollment is 100, and its status is completed. The study is titled as a mobile-health pilot experiment targeting mothers with newborns in rural areas of San Juan Sacatepequez, Guatemala. The registry lists a start in 2013-11 and primary completion in 2014-05.

The intervention descriptions distinguish communication formats. The uni-directional SMS group received breastfeeding-promoting messages and could only receive texts. Participants in virtual communities could exchange infant-health messages by SMS as groups. The hybrid setup also used virtual communities but included a health professional. The control group was given a feature phone described as a simple mobile phone. The registry does not report all implementation details, such as how the groups were assigned in practice, the frequency of messages, or whether control participants received other study content.

Randomization is intended to make group assignment independent of participants’ measured and unmeasured characteristics, on average. That is a general design principle, not a guarantee that the groups were balanced in this particular trial. The allocation ratio, sequence-generation method, and concealment procedures are not reported in the registry record. The record calls the study double-masked, but does not identify which people were masked or explain how masking could be maintained across visibly different communication approaches.

A parallel design assigns participants to groups that are followed over the same study period, rather than having each participant receive multiple approaches in sequence. The primary outcome timeframe is December 2013 - May 2014, 23 weeks. The registry also lists infant mean change in weight-for-age Z-score and text-message characteristics among secondary outcomes. It does not report group-specific primary outcome results, a statistical analysis plan, or the number of participants analyzed for the primary endpoint.

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

5. Baseline Characteristics

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

Population: Indigenous women from San Juan Sacatepequez

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Changes in Knowledge, measured over December 2013 - May 2014, 23 weeks.

The primary endpoint is titled Number of Participants With Changes in Knowledge. It counts participants according to how their knowledge of exclusive breastfeeding changed over the experiment. The registry describes transitions from incorrect to correct knowledge as learning the message, and transitions from correct to incorrect knowledge as forgetting it. It also distinguishes participants who remained unaware from those who retained correct knowledge.

This kind of endpoint is used to describe both direction and persistence of knowledge over time. Looking only at knowledge at the end could combine participants who learned during follow-up with participants who already knew the correct information and retained it. Conversely, the transition categories make it possible to distinguish retention from new learning and loss of previously correct knowledge. This is a general measurement rationale; the registry does not explain the endpoint’s development or validation.

The outcome is reported as a number of participants, not as a continuous score. The timeframe is December 2013 - May 2014, 23 weeks. Although the registry identifies the categories of change, it does not report the observed category counts, group-specific estimates, or a single primary contrast among the groups. Accordingly, the endpoint’s definition is available, but the magnitude and precision of the observed changes are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registered design is randomized, double-masked, and parallel. These labels describe the intended structure, but they do not supply the details of the statistical analysis. The registry record does not report a primary analysis method, a model, a planned contrast, or a method for handling missing outcome data. The following statistical concepts are general explanations of how such trial data might be considered; they are not claims about methods used in this study.

What does randomization contribute?

As a general principle, random assignment aims to reduce systematic differences between intervention groups at the point of assignment. If the assignment process is implemented as intended, comparisons can be interpreted as contrasts between assigned groups, subject to chance imbalance, missing data, adherence, and other design limitations. The record does not describe sequence generation, allocation concealment, or the allocation ratio, so those features cannot be evaluated for this trial.

The listed approaches differ in their communication content and structure: one group received one-way messages, another participated in SMS virtual communities, and a hybrid group included a health professional in a virtual community. The control group received a feature phone. A comparison among these approaches would need to specify which groups are being contrasted and what outcome definition is used. No such primary contrast is reported in the registry record.

How could a categorical knowledge outcome be analyzed?

As a general matter, a transition outcome can be summarized by counting participants in each defined transition category, separately by randomized group. A comparative analysis could then focus on a prespecified category or on a joint comparison of the category distribution. The interpretation depends on the chosen estimand: for example, the question might concern learning specifically, or the overall distribution across learning, forgetting, remaining unaware, and remembering. Those are not interchangeable questions. The registry describes the categories but does not report a statistical method or identify a primary contrast.

For counts, the analysis also needs a denominator. A count of participants who learned the message has a different interpretation if the number assessed differs across groups. General reporting practice is to state both counts and denominators, along with the handling of participants without measurements at either assessment. These details are not reported in the registry record. No rates, relative effects, or other derived estimates should be inferred from the available entries.

What do masking and parallel follow-up mean statistically?

Double masking is a registry design label, but the people masked and the masking procedures are not described. In general, masking may limit the influence of expectations on assessments or decisions, depending on who is masked and how the outcome is measured. Different phone and communication formats may make participant masking difficult, but the record does not explain the practical masking arrangements. No conclusion about the success of masking can be drawn from the label alone.

In a parallel design, assigned groups are followed over the same study period. The primary outcome concerns change from earlier to later knowledge, so the analysis depends on measurements at both points. General statistical approaches may compare transition categories or model repeated measurements, but the appropriate approach depends on the collected data and the prespecified question. The registry does not report whether repeated-measure models, categorical tests, or another method were used.

Why do uncertainty and sample-size planning matter?

As a general explanation, an estimate describes the size and direction of an observed contrast, while an uncertainty interval communicates its precision under the model and assumptions used. A p-value, when reported, addresses compatibility with a specified null model; it does not indicate the probability that a treatment works or that a result is true. None of these quantities is reported for the primary endpoint in the registry record.

The registry includes planning assumptions for a sample-size illustration: 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 fraction of the observed effect. It also states that this illustration is computed from the observed effect and is not the trial’s own design. No numerical sample-size illustration or observed effect is reported in the registry record. Such planning illustrations are not observed power and cannot replace the trial’s outcome estimates. The registry does not report the trial’s own sample-size justification or whether any interim analyses were planned or conducted.

Over-dispersion is a general issue for count outcomes when variability exceeds what a chosen count model assumes. If present, it can make standard errors too small under an overly restrictive model, affecting uncertainty estimates and tests. The registry does not provide the outcome data or model diagnostics needed to assess over-dispersion, and it does not report a count-model analysis. It would therefore be inappropriate to assert that over-dispersion occurred or that any particular correction was applied.

10. Multiplicity, Missing Data and Analysis Populations

The study lists several intervention approaches, a control group, a primary outcome with multiple knowledge-transition categories, and secondary outcomes concerning message characteristics, message exchanges, and infant weight-for-age Z-score. This creates several possible questions and comparisons. As a general statistical principle, when many hypotheses are tested, the chance of at least one apparently unusual result can increase unless the analysis plan accounts for multiplicity or clearly distinguishes primary from exploratory analyses.

The registry identifies a primary outcome but does not report a prespecified comparison among groups or categories, a multiplicity adjustment, a hierarchy of hypotheses, or an analysis plan. It is therefore not possible to determine which comparisons were planned, whether any adjustment was used, or how secondary findings were intended to be interpreted. The number of analyses listed is 0, which does not supply the missing methods or outcome estimates.

Missing data are also important for a change outcome because participants need information across the assessment period to be classified into a transition pattern. The registry record does not report how many participants completed each assessment, the amount or pattern of missingness, reasons for missing observations, or the method used to handle them. It does not state whether the primary analysis followed randomized assignment regardless of participation or instead used a restricted set of participants.

The record lists enrollment of 100 but does not identify the primary analysis population or group-specific analysis denominators. Safety entries contain separate at-risk counts, but they do not define the population used for the knowledge endpoint. Without these details, the completeness and comparability of the primary outcome data cannot be assessed. These omissions limit interpretation of both the validity and the precision of any group comparison.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry’s safety entries report zero serious adverse events and zero other adverse events in each listed group. The at-risk counts listed are 20 for Uni-directional SMS, 24 for Virtual Communities, 22 for Hybrid Setup, and 12 for Control Group. These are the figures recorded for the safety entries; they should not be treated as the primary outcome analysis denominators.

The deaths field is null for each group. A null entry is not a reported count of zero. Death information is therefore not reported in the registry record. The entries also do not give descriptions of adverse events, event definitions, collection procedures, or follow-up details. No serious adverse-event terms are listed.

As a general statistical point, observing no reported events in a group does not establish that the underlying risk is absent. The interpretation depends on the completeness and duration of safety monitoring, the number of participants assessed, and how events were defined and recorded. Those details are not reported in the registry record. The listed zero counts describe the registry entries, not proof that no adverse events occurred outside the recorded data.

The registry lists enrollment of 100, while the safety entries contain their own at-risk counts. The record does not explain the relationship between those figures, so they should not be reconciled by assumption. These safety entries do not provide evidence about the primary knowledge outcome or the secondary weight outcome.

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

The registry record shows that the study was designed to examine mobile-health communication about exclusive breastfeeding among mothers with newborns in rural areas of San Juan Sacatepequez, Guatemala. It identifies a randomized, double-masked, parallel design and describes three communication approaches alongside a control group given a feature phone. The primary endpoint concerns transitions in participants’ knowledge during the experiment.

What the record does not show is the observed distribution of those knowledge transitions. It gives no group-specific counts, effect estimates, confidence intervals, or p-values for the primary outcome. It also does not report results for infant weight evolution or the listed secondary outcomes. Consequently, the available registry information cannot establish whether any group had more learning, less forgetting, or a different overall pattern than another group.

That limitation should not be confused with a finding of no difference. A missing result is not the same as an estimate near zero, and it does not show that groups were equivalent. Without results and uncertainty measures, the direction, magnitude, and precision of comparisons are unknown. The registry’s completed status and enrollment listing do not fill that evidentiary gap.

More generally, even when outcome estimates are available, a pilot study’s findings need to be read in light of its design, sample size, follow-up, measurement quality, and analysis plan. The registry does not report enough information to assess the sample-size rationale, implementation fidelity, missing data, or primary analysis population. These are limits on what can be concluded from the record, rather than evidence that the study did or did not achieve its aims.

The registry’s safety entries record zero serious and zero other adverse events for each group, but deaths are not reported there. These entries should be read narrowly as the posted safety information, not as a full evaluation of safety. Overall, the registered question is clear, but the outcome evidence needed to answer it is not reported in the registry record.

13. Why This Trial Matters Statistically

This trial is statistically notable for asking a question that involves both communication delivery and change in knowledge. The approaches were not merely different message contents: they included one-way SMS, group exchanges by SMS, and a hybrid virtual community that included a health professional. The primary outcome also distinguishes learning from retention, forgetting, and remaining unaware. Those distinctions illustrate why defining the estimand—the precise quantity a study seeks to estimate—is important. This is a general statistical point, not an assertion about an analysis conducted in this trial.

The pilot setting is relevant to interpretation because a feasibility-oriented experiment can inform how an intervention is delivered and measured, but it does not automatically provide a definitive estimate of effectiveness. The registry describes the work as a pilot experiment in its title. It does not report a sample-size justification or a statistical plan, so the intended role of any estimates cannot be assessed beyond that description.

From a biostatistical perspective, the record also highlights the importance of registering operational definitions and analysis details. A transition outcome requires observations over time and decisions about how to classify incomplete assessments. A multi-group study with several outcome categories requires clarity about the intended comparisons and multiplicity. Those details help readers distinguish a prespecified primary question from exploratory analyses. They are not reported in the registry record.

Finally, the posted entry illustrates the difference between a study’s question and its answer. The registry gives enough design information to understand the general comparison, but it does not include the primary outcome results needed to quantify a contrast or its uncertainty. A clearly stated research question is valuable, yet statistical interpretation requires observed data, denominators, analysis methods, and uncertainty measures as well. Without those, no comparative conclusion can be supported from this record.

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.

Several trial-specific details needed to judge the evidence are not reported in the registry record. The eligibility criteria beyond the population description, recruitment procedures, allocation ratio, randomization sequence method, and allocation concealment are not described. Although the design is labeled double-masked, the masked parties and procedures are unspecified. The three communication formats also differ in structure, so the record does not make clear which features were intended to isolate a particular intervention component.

The primary outcome is described through knowledge transitions over the experiment, but the record does not define the assessment instrument, the exact classification rules, or how knowledge was measured at each assessment. No observed category counts or group comparisons are reported. The relation between the registry’s total enrollment and the numbers listed at risk in the safety entries is not explained. Participant flow, outcome completion, reasons for missing data, and the primary analysis population are also not reported.

The registry lists secondary outcomes for message content, message volume, and infant weight-for-age Z-score, but does not report their results. It does not provide details needed to evaluate outcome measurement, implementation fidelity, intervention exposure, or follow-up completeness. The statistical analysis plan, model specification, handling of multiplicity, and missing-data method are not reported. The trial’s own sample-size rationale and any interim analyses are also not reported in the registry record.

These limitations constrain interpretation of the entry; they do not establish that the trial lacked those procedures or that the study data were incomplete. They mean only that the registry record does not document them. Most importantly, without primary outcome results and their uncertainty, the registered comparison cannot be quantitatively evaluated.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Mobile-health Pilot Experiment Targeting Mothers With Newborns in Rural Areas of San Juan Sacatepequez, Guatemala — NCT02263118.
• Registry record last updated 2015-07-22; status last verified 2015-06.
• Results first posted 2015-06-30.
• 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

The registry describes a completed randomized, double-masked, parallel pilot experiment with enrollment of 100. It concerns mothers with newborns in rural areas of San Juan Sacatepequez, Guatemala, and compares one-way breastfeeding-promoting SMS, SMS virtual communities, a hybrid virtual community with a health professional, and a control group given a feature phone. The primary outcome is the number of participants with changes in knowledge of exclusive breastfeeding during December 2013 - May 2014, 23 weeks.

The outcome description distinguishes learning, forgetting, remaining unaware, and remembering the message. The registry record does not report the observed primary outcome counts, a comparative analysis, confidence intervals, or p-values. Results for the listed secondary outcomes are also not reported in the registry record. Safety entries list zero serious and zero other adverse events for each group; deaths are not reported. Important analysis details, including the primary analysis population, missing-data handling, and multiplicity procedures, are not reported in the registry record.