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 Transferability and Cost-effectiveness of PROSPECT in Surgical Trainees (NCT01965860), a randomized na study. The primary outcome is Technical and Global Performance of the Surgical Trainee in Real Life Procedures.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01965860 |
| Phase | NA |
| Condition | Vascular Disease |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 39 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University Ghent |
| Results posted | Yes |
2. Clinical Question
Population
Surgical trainees taking part in a study of endovascular skills for management of symptomatic vascular disease in the lower limbs. The registry record lists enrollment of 39, but does not report a fuller description of participants or the number included in each primary-outcome analysis.
Intervention
PROSPECT, a stepwise curriculum combining four E-learning modules with practical simulation exercises. The modules cover basic endovascular skills, the iliac artery, the superficial femoral artery and postoperative care. Trainees complete a multiple-choice questionnaire and perform a simple and a complex exercise after each module.
Comparator
The study includes a control group continuing clinical education without an additional curriculum, while being allowed to study independently. A third group receives the four E-learning modules and questionnaires but no simulation. This makes it possible to distinguish the curriculum with simulation from E-learning alone and from usual clinical education, although numerical comparisons are not reported in the registry record.
Primary question
At 6 weeks after the intervention, how do trainees perform in real-life endovascular procedures, as assessed by a consultant and by later review of recorded procedure material? The registry describes global and technical performance scores as well as procedural surrogate measures. It does not report numerical results for those measures or a single reduced comparison.
3. Trial Design
This was a randomized, parallel-group study with single masking. The registry record lists the phase as NA and the status as completed. Enrollment was 39. The study dates recorded are 2014-08 for the start and 2016-02 for primary completion. University Ghent is listed as the sponsor.
The three study groups are PROSPECT, E-LEARNING and CONTROL. PROSPECT combines four E-learning modules with simulation: after studying each module, the trainee completes a multiple-choice questionnaire and performs a simple and a complex exercise. The E-LEARNING group studies the same four modules and completes questionnaires, but receives no simulation. The CONTROL group continues clinical education without an additional curriculum, with independent study allowed.
The study description frames its purpose as designing, validating and assessing the cost-effectiveness of a comprehensive endovascular simulation curriculum involving cognitive and psychomotor skills training. However, the registry record does not report cost-effectiveness results, a detailed economic evaluation, or the results needed to judge comparative performance. The reported secondary outcome concerns improved knowledge and technical performance on a simulated complex module.
The primary outcome is assessed in real-life procedures within six weeks after curriculum completion. The record describes two procedures in that period. Evaluation includes consultant ratings during the intervention and later ratings of videos of hand movements and fluoroscopy imaging. It also lists procedural measures such as total procedure time, fluoroscopy time, radiation dose, contrast volume and number of endovascular tools used. The registry record does not report the allocation ratio, the masking details, or how randomization and allocation concealment were implemented.
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: 7 people declined to participate before randomisation during the RCT
Overall Study
| Stage | PROSPECT | E-LEARNING | CONTROL |
|---|---|---|---|
| STARTED | 11 | 10 | 11 |
| COMPLETED | 9 | 10 | 10 |
| NOT COMPLETED | 2 | 0 | 1 |
Reasons for not completing this period:
| Reason | PROSPECT | E-LEARNING | CONTROL |
|---|---|---|---|
| Pregnancy | 1 | 0 | 1 |
| Logistics | 1 | 0 | 0 |
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: 39 surgical trainees were eligible to start the RCT. Randomisation took place after screening for eligibility.
| Characteristic | Unit | PROSPECT | E-LEARNING | CONTROL | Total |
|---|---|---|---|---|---|
| Participants analysed | 11 | 10 | 11 | 32 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 11 | 10 | 11 | 32 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 | 0 |
| Sex: Female, Male: Female | Participants | 5 | 6 | 5 | 16 |
| Sex: Female, Male: Male | Participants | 6 | 4 | 6 | 16 |
| Postgraduate year: Level 1 | Participants | 2 | 3 | 4 | 9 |
| Postgraduate year: Level 2 | Participants | 2 | 3 | 1 | 6 |
| Postgraduate year: Level 3 | Participants | 4 | 1 | 3 | 8 |
| Postgraduate year: Level 4 | Participants | 0 | 2 | 1 | 3 |
| Postgraduate year: Level 5 | Participants | 1 | 1 | 1 | 3 |
| Postgraduate year: Level 6 | Participants | 2 | 0 | 1 | 3 |
| No. endovascular cases assisted: 0-5 | Participants | 1 | 2 | 2 | 5 |
| No. endovascular cases assisted: 5-10 | Participants | 2 | 1 | 1 | 4 |
| No. endovascular cases assisted: 10-50 | Participants | 6 | 5 | 1 | 12 |
| No. endovascular cases assisted: 50-100 | Participants | 1 | 1 | 5 | 7 |
| No. endovascular cases assisted: 100-200 | Participants | 1 | 0 | 0 | 1 |
| No. endovascular cases assisted: > 200 | Participants | 0 | 1 | 2 | 3 |
6. Primary Endpoint
The registry lists the primary outcome as Technical and Global Performance of the Surgical Trainee in Real Life Procedures, measured over 6 weeks after intervention.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | score on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint concerns technical and global performance of a surgical trainee during real-life endovascular procedures, assessed 6 weeks after the intervention. The consultant rates performance during the intervention; hand-movement videos and fluoroscopy imaging are also evaluated afterwards using the stated scoring systems. The record describes two real-life procedures within six weeks after curriculum completion.
Global performance is rated with the Global Rating Scale of Endovascular Performance, with a range of 11-55. Technical performance is rated with an Examiner Checklist for Diagnostic Angiography, Angioplasty and Stenting, with a range of 17-85. For both scales, higher scores indicate better performance. These ratings aim to capture different aspects of operator performance rather than relying only on whether a procedure was completed.
The registry also describes surrogate measures: total procedure and fluoroscopy time, radiation dose, contrast volume and number of endovascular tools used. Such measures can add detail about how a procedure was performed, but their interpretation depends on how they are defined and analyzed. The registry record does not report numerical endpoint summaries, variability, comparisons between groups, or how the multiple measures were combined. It therefore does not establish the direction or precision of any group difference.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record provides a clear description of the three training approaches and the intended performance assessments, but it does not provide numerical results for the primary outcome. In particular, no group means, standard deviations, effect estimates, confidence intervals or p-values for the global or technical performance scores are reported in the record. The outcome entry describes a mean and standard deviation as the summary format, but does not give the values. The listed surrogate measures also have no numerical results in the record.
Consequently, the comparative performance of PROSPECT, E-LEARNING and CONTROL cannot be judged from these registry entries. The fact that the trial is marked completed does not itself supply evidence about the direction or size of any difference. Nor can the listed enrollment alone establish the precision of an estimate, since the number of participants contributing to each endpoint analysis is not reported.
The study includes three educational strategies with potentially informative contrasts: curriculum plus simulation, E-learning without simulation, and continued clinical education without an additional curriculum. However, the registry record does not report the actual analyses by group or identify a single numerical contrast for the primary endpoint. The primary outcome entry notes several categories or time points and is not reduced to one comparison. It would be inappropriate to select one score or surrogate measure as the definitive result without an explicit reported analysis.
For continuous outcomes, a mean difference can describe how far apart group averages are, while a confidence interval conveys uncertainty around that estimate. A p-value addresses compatibility with a specified null model, but does not describe the magnitude or practical importance of a difference. These are general statistical interpretations; the registry record contains no such estimate for the primary measures. Without estimates and intervals, neither the size nor the precision of group differences can be assessed.
The sample-size illustrations are planning calculations based on an observed effect and stated assumptions, rather than evidence that the study had a particular probability of detecting an effect. They are not observed power and do not replace the trial's actual results. The registry record does not report the study's own sample-size justification or the effect used in its original design. No conclusion about training efficacy, comparative benefit or cost-effectiveness follows from the descriptive registry information alone.
9. Statistical Methods Explained
The registry identifies the study as randomized, single-masked and parallel-group, with three groups. These terms describe broad design features, not all details of how the study was conducted. The registry record does not report the random sequence method, allocation concealment, who was masked, or whether masking was maintained. The phase is recorded as NA.
What does a continuous outcome summary mean?
The primary outcome is described using means and standard deviations. In general, a mean summarizes the center of a set of measurements, while the standard deviation describes how spread out individual measurements are around that center. Both can help characterize performance scores, but neither alone expresses the uncertainty in a comparison between groups. For that, an analysis may report a difference in means together with a confidence interval. The registry record does not report these numerical summaries or comparison estimates for the primary outcome.
The two rating instruments assess global and technical performance, respectively. The Global Rating Scale of Endovascular Performance has a range of 11-55, and the Examiner Checklist for Diagnostic Angiography, Angioplasty and Stenting has a range of 17-85. The record states that higher scores are better for both. This direction statement helps interpret a score if reported; it does not reveal the results of this study. The record does not describe score distributions, assessor agreement, or whether ratings from the two procedures were averaged or analyzed separately.
How should multiple performance measures be understood?
The primary outcome description includes two rating scales and several surrogate measures: total procedure time, fluoroscopy time, radiation dose, contrast volume and number of endovascular tools used. These measures represent different features of a procedure and do not necessarily have a common scale or a single interpretation. General statistical practice requires clear definitions, appropriate summaries and a prespecified approach to comparing groups. The registry record does not report the analysis details for these measures, including whether results were adjusted, combined, or treated as separate endpoints.
The record also lists a secondary outcome concerning knowledge and technical performance on a simulated complex module. It records 3 outcome measures and 10 analyses, but does not explain how those analyses map to endpoints or which comparison should be treated as primary among them. The primary outcome description itself includes several categories or time points and is not reduced to one comparison. This complicates a concise reading of statistical evidence because many possible estimates may be relevant.
What does a confidence interval add?
In general, a confidence interval gives a range of values compatible with the observed data under the method's assumptions. A narrow interval indicates greater precision than a wide interval, though the meaning of the interval depends on the outcome scale and analysis. It is not a guarantee that the true value falls within the interval, and it does not by itself determine clinical or educational importance. No confidence intervals for the primary endpoint are reported in the registry record.
A p-value, when available, summarizes how unusual data at least as extreme as those observed would be under a specified null hypothesis and model. It is not the probability that the null hypothesis is true, and it does not measure the size of a difference. The registry record does not report primary-outcome p-values, so statistical significance cannot be assessed from the record.
What do the planning illustrations represent?
The stated sample-size assumptions describe a planning illustration computed from an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms and a normal approximation. For non-time-to-event outcomes, the illustration is expressed as participants per arm for 80% power or other stated planning levels; time-to-event calculations use a total number of events. The effect to detect is expressed as a stated fraction of the observed effect. These are planning illustrations, not enrollment results, and they are not observed power.
General sample-size calculations estimate the amount of information needed under chosen assumptions. Their output depends on the effect size, variability, allocation and analysis method. A calculation based on an observed effect is especially illustrative because that observed effect may be uncertain. The registry record does not report the trial's own design justification, planned target effect, or full statistical analysis plan. The assumptions listed for planning illustrations should therefore not be mistaken for documented protocol decisions.
Over-dispersion is a general concern when outcomes vary more than the statistical model expects. If ignored, uncertainty may be understated and inferential results can be too optimistic. The primary score is continuous, and the registry record does not report whether over-dispersion was assessed or whether any model adjustments were used. This is a general methodological consideration, not a claim that over-dispersion occurred in this study.
10. Multiplicity, Missing Data and Analysis Populations
The record lists 3 outcome measures and 10 analyses, as well as multiple performance measures and several categories or time points in the primary-outcome description. It does not report a multiplicity strategy, such as a hierarchy of outcomes, an adjustment to control the chance of false-positive findings across analyses, or a prespecified rule for selecting the main comparison. Without that information and the corresponding estimates, the many potential comparisons cannot be interpreted as a single confirmatory result.
The registry record does not report missing-data counts, reasons for missing measurements, imputation methods, or sensitivity analyses. It also does not describe the analysis population, such as whether analyses followed randomized assignment or included only participants with complete assessments. Enrollment of 39 does not establish how many trainees contributed data to each outcome or analysis.
These omissions matter because missing outcome data and analysis-population choices can affect both the estimate and its uncertainty. In general, analyses restricted to participants with complete observations may be biased if missingness is related to performance or group assignment. This is a general consideration, not evidence that bias occurred in this study. The registry record does not report enough detail to assess it.
The primary outcome is not reduced to one comparison in the registry record, so there is no basis there for identifying one definitive primary contrast or determining how multiplicity was handled. The full statistical analysis plan and missing-data approach are not reported in 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 |
|---|---|---|---|
| PROSPECT | 0 | 11 | 0.0% |
| E-LEARNING | 0 | 10 | 0.0% |
| CONTROL | 0 | 11 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| PROSPECT | 0 of 11 |
| E-LEARNING | 0 of 10 |
| CONTROL | 0 of 11 |
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 |
|---|---|
| PROSPECT | 0 of 11 |
| E-LEARNING | 0 of 10 |
| CONTROL | 0 of 11 |
The registry lists serious adverse events, other adverse events and deaths by study group. For PROSPECT, 11 participants are listed at risk for serious events and 11 at risk for other events; zero are reported as affected in either category, and deaths are recorded as 0. For E-LEARNING, 10 are listed at risk in each category; zero are reported as affected, and deaths are recorded as 0. For CONTROL, 11 are listed at risk in each category; zero are reported as affected, and deaths are recorded as 0.
These figures describe what the registry record reports. They do not establish that no events occurred outside the recorded categories or observation period. The record does not provide event definitions, the duration of safety follow-up, details of ascertainment, or a narrative explaining how events were collected. It also lists no top serious-event terms. The figures should therefore be read as the registry's recorded counts, not as a comprehensive assessment of all possible harms or as evidence for a comparative safety conclusion.
In general, zero recorded events in a group does not mean the underlying event risk is known to be zero. Event counts are most informative when read alongside the number observed, follow-up duration and completeness of reporting. Those details are not fully reported in the registry record.
12. What the Result Does, and Does Not, Mean
The registry record describes a randomized comparison of three educational approaches for surgical trainees and specifies how real-life endovascular performance was intended to be evaluated. It establishes that the primary assessment focused on global and technical ratings, supplemented by procedural measures, at 6 weeks after the intervention. It also gives the score ranges and states that higher ratings indicate better performance.
It does not report numerical results for those primary measures. No group-specific means, standard deviations, differences, confidence intervals or p-values are available in the record. As a result, the size, direction and precision of any observed difference cannot be described. The record also does not provide sufficient information to assess the secondary outcome or the cost-effectiveness objective.
The three-group structure could, in principle, help distinguish the contribution of simulation from E-learning and from clinical education without an additional curriculum. But a design's potential to answer a question is not itself an answer. Without reported group comparisons and analysis details, the relative performance of the training approaches remains undetermined by the registry record.
More generally, a statistical estimate would not by itself establish whether a difference is educationally meaningful. Interpretation would require the magnitude and uncertainty of the estimate, the outcome's measurement properties, and a clear account of how the comparison was selected. These results and contextual details are not reported in the registry record.
The completed status and enrollment count are study-record details, not outcome findings. The sample-size illustrations are planning aids rather than observed power or evidence that the trial detected a difference. Accordingly, the record supports a description of the study question and measurement strategy, but not a conclusion that one curriculum outperformed another or was cost-effective.
13. Why This Trial Matters Statistically
This study is statistically interesting because the intervention is not a simple two-arm contrast. PROSPECT combines E-learning with simulation, E-LEARNING includes the online modules without simulation, and CONTROL continues clinical education without an additional curriculum. In principle, these groups allow distinct educational comparisons, but each needs to be defined and reported clearly. The registry record does not identify a single numerical primary comparison.
The primary assessments also span different kinds of information. Consultant ratings and post-hoc video ratings aim to capture global and technical performance, while time, radiation dose, contrast volume and tool use are surrogate measures. Such measures can complement one another, but their scales and meanings differ. Statistical reporting needs to make clear which outcomes were prioritized and how multiple measures were handled. That plan is not reported in the registry record.
Another important issue is the link between simulation performance and performance during real-life procedures. The study description includes both training exercises and assessments during clinical procedures, making transferability a central question. The registry record describes this rationale and the assessment approach, but numerical results are not reported. The question therefore remains distinct from a demonstrated finding.
For readers evaluating evidence, the key statistical contribution would be estimates of group differences with uncertainty, accompanied by transparent information about analyses, missing data and multiplicity. Without those details, the record is useful for understanding the intended design but cannot support a quantitative conclusion about training effects or cost-effectiveness.
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.
A central limitation of the available registry information is the absence of numerical results for the primary performance measures. The record describes scales, procedural surrogates and timing, but does not provide group summaries or comparative estimates. It is therefore not possible to assess effect magnitude, precision or consistency across measures from this record.
The number enrolled is recorded as 39, but the record does not state the number analyzed for each outcome or explain whether all randomized trainees contributed measurements. No missing-data accounting, analysis-population definition, or sensitivity analysis is reported. This limits assessment of attrition and the possibility that analyzed participants differ from those enrolled.
There are many potential outcomes and analyses: the endpoint description includes two rating scales, procedural surrogates, multiple procedures, consultant ratings and later video ratings. Although the record lists 3 outcome measures and 10 analyses, it does not explain their relationship or report a multiplicity plan. This makes it difficult to determine which findings, if available elsewhere, would represent the principal confirmatory comparison.
Important design details are also not reported in the registry record, including the allocation ratio, randomization procedure, allocation concealment, the identity of masked parties, assessor training or reliability, and the full statistical analysis plan. The record does not provide the original sample-size justification or enough information to determine how cost-effectiveness was evaluated. These are limitations of the registry information and should not be treated as proof that the study did not address them elsewhere.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Transferability and Cost-effectiveness of PROSPECT in Surgical Trainees — NCT01965860.
- Registry record last updated 2021-03-16; status last verified 2021-01.
- Results first posted 2021-03-16.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT01965860 is a completed, randomized, single-masked, parallel-group study sponsored by University Ghent. Enrollment was 39, and the phase is recorded as NA. The study concerns transferability and cost-effectiveness of the PROSPECT proficiency-based endovascular training curriculum in surgical trainees.
Three groups are described: PROSPECT with E-learning and simulation, E-LEARNING with the modules but no simulation, and CONTROL continuing clinical education without an additional curriculum. The primary outcome concerns global and technical performance in real-life procedures, assessed 6 weeks after the intervention, alongside procedural surrogate measures. A secondary outcome concerns knowledge and technical performance on a simulated complex module.
The registry record does not report numerical primary-outcome comparisons, missing-data methods, a multiplicity plan, or a full statistical analysis plan. It records zero serious adverse events, other adverse events and deaths in each listed group. These registry entries describe the intended study and recorded counts but do not establish comparative performance or cost-effectiveness.