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 Using CHWs or Mailing Self Sampling Home Tests to Increase Cervical Cancer Screening in South Florida (NCT02202109), a randomized na study. The primary outcome is Number of Participants Completing a Self-sampling Test.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02202109 |
| Phase | NA |
| Condition | Cervical Cancer |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 602 |
| Arms in the primary outcome | 2 |
| Lead sponsor | University of Miami |
| Results posted | Yes |
2. Clinical Question
Population
Participants in South Florida communities described as lacking access to medical care. The registry reports enrollment of 602; it does not give further demographic details in the record.
Intervention
Self-sampling supported by a community health worker (CHW), including a home visit, provision of a self-sampler and collection of the test.
Comparator
A self-sampler mailed to the participant, with follow-up by phone.
Primary question
How many participants completed a self-sampling test within the stated period of 2 to 6 months, and how did the posted counts compare between the CHW-facilitated and mailed approaches?
The trial addresses whether the way a home self-sampling test is offered is associated with completion. Both approaches involve self-sampling, while one includes a CHW home visit and the other uses the mail with phone follow-up. The registry identifies the primary outcome as the number of participants completing a self-sampling test. Its description defines the outcome as having had self-sampling since the initial evaluation, and says participants could have up to 6 months to complete it.
The question is about completion of the test, not the accuracy of test results, a diagnosis, or subsequent health outcomes. The record describes intended follow-up pathways for negative and positive HPV test results, but the posted primary result does not report those pathways or their outcomes. The record also lists changes in cervical cancer knowledge and access to care as secondary outcomes. It does not report numerical results for those outcomes in the posted results.
3. Trial Design
The registry describes a randomized, parallel-group trial with single masking. The identity of the masked party is not reported in the registry record, nor is the method used to generate or conceal the random allocation. The study is listed as completed. It began in 2015-01, with primary completion in 2017-08. Its phase is recorded as NA, and the sponsor is the University of Miami.
Participants were assigned to CHW-facilitated self-sampling or mailed self-sampling. The CHW approach involved a home visit, a self-sampler and collection of the test. In the mailed approach, the self-sampler was sent to the participant, with follow-up by phone. These are behavioral interventions rather than drug or device treatment arms, as classified in the registry.
The registry reports enrollment of 602. The primary outcome entries list 272 for the CHW-facilitated arm and 257 for the mailed arm, with each count matching the corresponding arm count displayed for that outcome. These figures are not interchangeable: enrollment and the outcome entries are separately reported quantities. The record does not explain the relationship between the enrollment figure and the outcome counts, or state why the listed counts differ from enrollment.
The primary outcome timeframe is 2 to 6 months. The outcome description says participants were given up to 6 months to complete HPV self-sampling. The brief study summary describes an intended enrollment of 700, which differs from the reported enrollment of 602. The reason for that difference is not reported in the registry record. A detailed protocol, eligibility criteria, recruitment process and statistical analysis plan 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
| Stage | CHWs Facilited Self-Sampling | Mailed Self-Sampler |
|---|---|---|
| STARTED | 302 | 300 |
| COMPLETED | 212 | 213 |
| NOT COMPLETED | 90 | 87 |
Reasons for not completing this period:
| Reason | CHWs Facilited Self-Sampling | Mailed Self-Sampler |
|---|---|---|
| Lost to Follow-up | 88 | 87 |
| Withdrawal by Subject | 2 | 0 |
Analysis population for the primary outcome, as defined in the registry: Participants were given up to 6 months to complete HPV self-sampling.
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 | CHWs Facilited Self-Sampling | Mailed Self-Sampler | Total |
|---|---|---|---|---|
| Participants analysed | 302 | 300 | 602 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 302 | 300 | 602 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Female | Participants | 302 | 300 | 602 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 198 | 197 | 395 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 103 | 103 | 206 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 1 | 0 | 1 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 106 | 113 | 219 |
| Race (NIH/OMB): White | Participants | 141 | 138 | 279 |
| Race (NIH/OMB): More than one race | Participants | 54 | 47 | 101 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 1 | 2 | 3 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants Completing a Self-sampling Test, measured over 2 to 6 months.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the number of participants completing a self-sampling test. The registry describes completion as having had self-sampling since the initial evaluation, with a stated timeframe of 2 to 6 months and up to 6 months allowed for completion. It is a count outcome: it records participants with the event of interest, rather than measuring the amount of change in a continuous scale.
Completion is used to assess whether participants reached the step of conducting a home HPV self-sampling test. This outcome is relevant to the trial’s comparison because the two randomized approaches differ in how the self-sampler is delivered and supported. The endpoint does not measure whether a participant’s test was positive or negative, whether a positive result led to follow-up care, or whether screening affected later health outcomes.
The posted counts are 272 for the CHW-facilitated arm and 257 for the mailed arm. The corresponding listed arm counts are also 272 and 257. The registry does not describe how missing or incomplete outcome information was handled, or whether the displayed arm counts represent all participants randomized, participants with outcome data, or another analysis population. That limits interpretation of the count as a complete account of completion among everyone enrolled or randomized.
7. Results Posted in the Registry
- Mailed Self-Sampler: 100.0% (257/257) versus 100.0% (272/272) on control; risk difference 0.0 percentage points (95% CI 0.0 to 0.0), risk ratio 1.00 (1.00–1.00); unadjusted two-proportion z-test p = n/a.
Risk difference: Mailed Self-Sampler
95% CI: 0.0 to 0.0 percentage points
Recalculated from the posted summary statistics
8. Statistical Interpretation
The registry reports 272 participants with the primary outcome in the CHW-facilitated arm and 257 in the mailed arm. The corresponding arm counts listed for this outcome are 272 and 257. The posted comparison gives a risk difference of 0, with a confidence interval from 0 to 0 and p = 1.0. It also reports values of 1.0 for the relative risk and its interval. The displayed comparison therefore expresses no difference between the arm-level proportions as reported by the registry.
Those entries need to be read alongside the counts rather than as proof that the two delivery approaches are equivalent in every relevant respect. The record does not report an equivalence or noninferiority objective, a margin for such a conclusion, or a detailed analysis plan. A conventional test result of p = 1.0 is not a probability that the approaches are identical, and it does not establish that any possible difference is unimportant. It describes the result of the comparison as recorded, under an analysis method that is not detailed in the registry record.
The count values match their respective listed arm counts. On their face, these entries indicate a recorded outcome for every participant represented by those arm counts, but the record does not explain whether that interpretation applies to everyone enrolled or randomized. Enrollment is reported separately as 602, and the reason for the difference between enrollment and the outcome-entry counts is not reported in the registry record. Without a participant flow account, the scope of the outcome counts remains uncertain.
The displayed risk difference and confidence interval all have endpoints of 0. This is an unusually uninformative way to convey precision if interpreted literally, because the interval has no width at the displayed precision. The registry does not explain the interval calculation or provide additional digits. The result should therefore be described as the posted estimate and interval, not treated as proof of no uncertainty or as evidence that small differences have been ruled out.
The record identifies two secondary outcomes: change in cervical cancer knowledge and change in access to care. Numerical findings for them are not reported in the registry record. It also lists three outcome measures and zero analyses. No adjusted estimates, subgroup results, or detailed model outputs are reported in the registry record. As a result, the posted primary comparison supports only a narrow description of the recorded completion counts and their reported comparison. It does not establish how the approaches compare on other outcomes, or how results might differ across participant groups.
9. Statistical Methods Explained
The registry identifies the study as randomized and parallel-group. In a randomized study, allocation is intended to assign participants to study approaches by chance rather than by a clinician’s or participant’s preference. In general, random allocation can reduce systematic differences between groups at the start of a study. It does not guarantee that groups are identical, and the record does not provide baseline characteristics with which to assess their comparability. The allocation sequence and concealment procedures are not reported in the registry record.
What does the risk difference describe?
For a binary outcome such as completion or non-completion, a risk is the proportion of participants in a group who have the outcome. A risk difference expresses the difference between the proportions in the two groups. It is on the scale of the outcome proportion, so a value of 0 indicates equal reported proportions. The registry gives a risk difference of 0 for the mailed approach in comparison with the CHW-facilitated approach. Its reported interval also runs from 0 to 0.
The registry also reports a relative risk of 1.0, with interval values of 1.0. A relative risk compares the outcome risk in one group with that in another. A value of 1 indicates equal reported risks. Risk differences and relative risks describe the same comparison on different scales; neither one by itself establishes that an observed difference is clinically important or unimportant. The record does not report adjusted versions of these measures.
What does the p-value tell the reader?
A p-value describes how compatible observed data are with a specified null hypothesis under a statistical model. It is not the probability that the null hypothesis is true, and it does not measure the size or practical importance of a difference. Here, the registry reports p = 1.0 for the primary comparison. The precise test and its assumptions are not reported in the registry record. The p-value should therefore be interpreted as the registry’s posted result, not as a substitute for understanding the outcome counts, the interval or the analysis population.
Why does the analysis population matter?
Statistical comparisons depend on who is included and how outcome information is handled. An analysis restricted to participants with an observed outcome can differ in meaning from an analysis that includes everyone as randomized. The record gives the enrollment figure and arm-level outcome counts, but does not report a participant flow, the number randomized to each arm, or a named analysis population. It also does not explain missing-data rules. These omissions prevent a clear assessment of whether the comparison follows an intention-to-treat principle or another approach.
How should the confidence interval be read?
In general, a confidence interval gives a range of estimates compatible with a statistical procedure and the observed data, while reflecting sampling uncertainty under its assumptions. A narrower interval indicates greater precision on the scale being reported; a wider interval indicates less precision. The registry’s interval for the risk difference has both endpoints at 0, the same as its estimate. No method or additional precision is reported. The displayed interval cannot be used to assess a plausible range of nonzero differences beyond what is explicitly shown.
What can be learned from the planning illustration?
The registry describes sample-size planning illustrations as based on the observed effect, using a two-sided significance level of 0.05, equal allocation and a normal approximation. It says the effect to detect is expressed as a fraction of the observed effect. These are planning assumptions, not results from the trial. The record does not report the sample-size illustration values in the information. Any such illustration would be hypothetical planning information and not observed power. It cannot replace a reported protocol-based sample-size justification, which is not reported in the registry record.
The record lists zero analyses despite posting a primary comparison. It does not detail the statistical procedure used to derive the comparison, whether any adjustments were made, or whether the comparison was prespecified in a protocol. No independent recalculation is presented as the primary result. The posted sponsor analysis takes precedence when the record supplies an analysis, and the record does not flag a discrepancy. General statistical concepts help explain the measures, but cannot fill in missing details about the actual analysis.
10. Confidence Intervals and Precision
Precision concerns how closely an estimate locates the underlying effect that the study seeks to describe. A confidence interval usually communicates this by showing a range of values compatible with the data and a specified statistical procedure. The registry reports a risk difference of 0 and an interval from 0 to 0 for the comparison of mailed with CHW-facilitated self-sampling. It also reports relative risk and interval values of 1.0.
Because the endpoints of the risk-difference interval coincide with the estimate, the posted interval does not display a range of uncertainty. The registry does not identify the interval method or explain why the displayed endpoints coincide. It also does not provide additional digits. The interval should not be expanded, recalculated or interpreted as demonstrating certainty beyond its displayed precision. The record does not report another uncertainty measure that would clarify the estimate.
The arm-level outcome counts are 272 and 257, matching the corresponding counts listed for those arms. But the record does not explain their relationship to enrollment of 602 or give a participant flow diagram or analysis population. Precision depends not only on a displayed interval but also on the correctness of the data and analysis underlying it. Without the denominator and missing-data details, the interval alone cannot resolve uncertainty about whom the primary comparison represents.
In general, a confidence interval that includes the null value does not establish equivalence, while a narrow and well-calculated interval can help rule out effects outside its range. Here, no equivalence margin is reported, and the interval as displayed has no range beyond its single value. The statistical precision of the primary effect cannot be evaluated confidently from the registry record alone.
11. Multiplicity, Missing Data and Analysis Populations
The registry lists one primary outcome and two secondary outcomes: change in cervical cancer knowledge and change in access to care. It reports three outcome measures and zero analyses. Numerical results for the secondary outcomes are not reported in the registry record. The record does not describe whether the secondary outcomes were analyzed, how they were defined, or how any results were handled.
When a study examines multiple outcomes or makes multiple comparisons, the chance of obtaining at least one apparently notable result can increase. Statistical methods may address this multiplicity, but whether adjustment is appropriate depends on the prespecified questions and analysis plan. The registry does not report a multiplicity strategy, a hierarchy among the outcomes, or a detailed analysis plan. No conclusions about adjustment or selective reporting can be drawn from these omissions alone.
Missing-data handling is also not reported in the registry record. The primary outcome counts match the corresponding listed arm counts, but the record does not clarify whether the counts cover everyone randomized, only participants with outcome information, or a different analysis population. It does not say how participants who did not return a kit, did not complete testing, or had unavailable outcome information were classified in the analysis. The outcome description says CHWs would follow up with participants who did not return a kit within 60 days, but does not report how follow-up affected analysis inclusion.
The total enrollment is reported as 602, while the two primary-outcome arm counts are reported separately as 272 and 257. The relationship among these figures, including whether any participants were not randomized or excluded from the outcome analysis, is not reported in the registry record. The record also does not report an intention-to-treat, per-protocol or other analysis population. These gaps limit interpretation of both the effect estimate and its precision.
12. 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 |
|---|---|---|---|
| CHWs Facilited Self-Sampling | 0 | 302 | 0.0% |
| Mailed Self-Sampler | 0 | 300 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| CHWs Facilited Self-Sampling | 0 of 302 |
| Mailed Self-Sampler | 0 of 300 |
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 |
|---|---|
| CHWs Facilited Self-Sampling | 0 of 302 |
| Mailed Self-Sampler | 0 of 300 |
The registry lists serious adverse events, other adverse events and deaths separately for the two study arms. For the CHW-facilitated arm, the record lists 0 serious adverse events and 0 other adverse events among 302 at risk, and 0 deaths. For the mailed arm, it lists 0 serious adverse events and 0 other adverse events among 300 at risk, and 0 deaths. No serious adverse event terms are listed.
These figures mean that the registry reports no events in the categories shown for the listed groups. They do not establish that the risk of an event is absent, nor do they show that the approaches have identical safety profiles. Event counts can be interpreted only in relation to the record’s reporting practices, observation period and population at risk. Those details are not reported in the registry record.
The adverse-event group counts differ from the primary-outcome arm counts, and the record does not explain the relationship between those populations. The adverse-event entries should therefore be read as a separate set of registry figures, not used as denominators for the completion comparison. They describe reported events and do not provide an estimate of comparative risk.
13. What the Result Does, and Does Not, Mean
The primary result is a registry-reported comparison of completion counts for two ways of providing HPV self-sampling: CHW facilitation and mailing with phone follow-up. The displayed counts are 272 and 257, respectively, and the corresponding arm counts are also 272 and 257. The reported risk difference is 0, its interval runs from 0 to 0, and p = 1.0. In the registry’s displayed comparison, the arm-level proportions are reported as equal.
That result does not by itself show that the two approaches are equivalent for all purposes. No equivalence or noninferiority framework, prespecified margin or detailed statistical analysis plan is reported in the registry record. The confidence interval’s displayed endpoints are identical, and the method behind it is not explained. The counts also do not establish how completion would compare in a different population or under different implementation conditions.
The primary endpoint is completion of self-sampling, not HPV status, follow-up care, cervical cancer diagnosis or a later health outcome. Although the record describes encouragement to rescreen after a negative test and navigation to follow-up care after a positive HPV result, it does not report results for those steps. The listed secondary outcomes concern knowledge and access to care, but numerical findings for them are not reported in the registry record.
The findings also do not establish that every participant enrolled was included in the primary comparison. Enrollment is reported as 602, while the outcome counts are reported separately, and the reason for the difference is not given. Missing-data handling and the analysis population are not reported in the registry record. The most defensible interpretation is therefore limited to the posted outcome counts and their stated comparison, with uncertainty about analysis details and the population represented.
14. Why This Trial Matters Statistically
Statistically, this trial illustrates how an apparently simple completion endpoint depends on clear definitions of both the outcome and the analysis population. The registry defines the primary outcome as having had self-sampling since the initial evaluation, within a stated timeframe of 2 to 6 months. It also reports an enrollment figure and separate arm-level counts that match the outcome counts. Without a participant flow account, readers cannot determine how those counts relate to the full enrolled or randomized population.
The study compares two delivery strategies that share the use of home self-sampling but differ in support and delivery: a CHW home visit versus mailing with phone follow-up. That design makes completion a directly relevant outcome for the stated comparison. At the same time, completion is only one step in the screening process. It does not reveal the test result, subsequent follow-up, or changes in knowledge and access to care. The distinction between a process outcome and later outcomes is important when interpreting what a trial has evaluated.
The posted estimate and interval also highlight the importance of transparent statistical reporting. A risk difference of 0 with an interval from 0 to 0 appears exact, but the method and underlying analysis details are not reported in the registry record. A reader cannot use that display alone to understand the range of plausible effects or judge the uncertainty. Reporting the analysis method, missing-data approach and analysis population would make the comparison easier to interpret.
Finally, the record lists secondary outcomes but does not report their numerical results, and it contains no detailed multiplicity plan. These omissions do not invalidate the posted primary comparison, but they limit the broader conclusions that can be drawn. The trial is statistically informative as an example of why transparent denominators, analysis methods and outcome reporting matter alongside a point estimate.
15. 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 leaves several trial-specific questions unresolved. It reports enrollment of 602, while the primary-outcome arm counts are 272 and 257. The record does not explain the relationship between these figures, provide participant flow, or state how many participants were randomized to each arm. It also does not identify the population included in the primary analysis or explain how missing outcome data were treated.
The posted risk difference is 0, with an interval from 0 to 0, but the method used to calculate the interval and the test is not described. No additional precision is given. The record reports zero analyses, despite listing a primary comparison, and does not provide a protocol or detailed statistical analysis plan. The meaning of single masking, including who was masked, is not reported in the registry record.
The brief summary describes an intended enrollment of 700, while the reported enrollment is 602; the reason is not reported in the registry record. The record also does not report the eligibility criteria, participant characteristics, baseline balance, or recruitment details needed to assess how closely the study population reflects the communities described. It identifies secondary outcomes but does not report their numerical findings or a multiplicity strategy.
The primary outcome concerns completion rather than the test result or subsequent care. The registry describes follow-up plans for positive and negative HPV results, but does not report whether these steps occurred or their outcomes. Adverse-event counts are reported, but their observation period and relationship to the primary-outcome population are not explained. These limitations constrain interpretation of the posted completion comparison and its applicability beyond the participants represented in the registry results.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Using CHWs or Mailing Self Sampling Home Tests to Increase Cervical Cancer Screening in South Florida — NCT02202109.
- Registry record last updated 2018-12-19; status last verified 2018-12.
- Results first posted 2018-12-19.
- 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.
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19. Record Summary
The registry describes a completed randomized, parallel-group study sponsored by the University of Miami, comparing CHW-facilitated cervical cancer self-sampling with mailed self-sampling and phone follow-up. It reports enrollment of 602, a primary completion timeframe of 2 to 6 months, and primary outcome counts of 272 and 257 for the respective arms. The posted comparison reports a risk difference of 0, an interval from 0 to 0, and p = 1.0. The record lists two secondary outcomes, but their numerical results are not reported in the registry record. It does not provide a detailed statistical analysis plan, missing-data approach, or explanation of the relationship between enrollment and the primary-outcome counts.