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 Effectiveness of a Computer Application in Improving Pulmonary Artery Catheter Waveform Interpretation (NCT00138073), a non-randomized na study. The primary outcome is Score on a Computer-based Test on Pulmonary Artery Catheter Waveform Interpretation.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00138073 |
| Phase | NA |
| Condition | Pulmonary Artery Catheter Waveform Interpretation |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 55 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Massachusetts General Hospital |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns nurses and physicians interpreting pulmonary artery catheter (PAC) waveforms. The registry record describes the intended audience but does not report further eligibility criteria, participant characteristics, or how the enrolled group was divided by profession.
Intervention
The intervention was access to a web-based waveform interpretation guide. The study description says the investigators developed a computer application intended to assist with PAC waveform interpretation. Details of the guide’s content, duration of access, or how participants were expected to use it are not reported in the registry record.
Comparator
The study is recorded as a single-group, non-randomized design, with no masking. It therefore does not provide a randomized control group for a like-for-like comparison. A separate comparator condition or an untreated group is not reported in the registry record.
Primary question
The stated primary question was whether the guide could improve performance on a computer-based test of PAC waveform interpretation. The planned outcome was a test score measured at 1 month. The registry record says the study was terminated before that outcome could be measured and that none of the participants took the post-intervention test. Consequently, the posted results cannot establish whether scores improved, stayed the same, or changed in another direction.
The study addresses an educational and assessment question: whether access to a digital reference can help clinicians interpret waveforms on a computer-based assessment. The record gives the intended purpose, but not enough outcome information to evaluate that purpose. It also does not report a comparator group that would help distinguish any change associated with the guide from other influences. The central finding is therefore about the availability of evidence: the planned primary test result is absent, rather than positive or negative.
3. Trial Design
The registry describes a single-group, non-randomized study with no masking. The intervention was a web-based waveform interpretation guide, and the arm description says the group had access to that guide. No separate control arm or randomized allocation is recorded. The registry lists enrollment as 55, but does not provide participant-level characteristics or explain how many enrolled participants completed any activities other than the post-intervention test, which none took.
The study’s primary outcome was a score on a computer-based test of PAC waveform interpretation, with a stated timeframe of 1 month. The registry explicitly reports that the study was terminated before this outcome could be measured. It also lists frequency of use and usage patterns of the guide as a secondary outcome. The registry does not report results for that outcome, and it records 0 analyses.
The study is marked as terminated. Its start is recorded as 2005-12 and its primary completion as 2012-04. The phase is listed as NA. These record details describe the study’s status and classification; they do not explain why it was terminated or establish that outcome collection occurred before termination. The reason for termination and the operational details of the study are not reported in the registry record.
Because the design has a single group and no randomized comparator, it cannot provide a randomized between-group estimate of the guide’s effect. That design description should not be mistaken for evidence of an observed change within participants: the registry says the post-intervention test was not taken. Whether the protocol included a baseline test, how the guide was introduced, or what analysis was planned is not reported in the registry record. Without those details and without measured primary outcomes, the design information alone cannot answer the effectiveness question.
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 | Web-based Waveform Interpretation Guide |
|---|---|
| STARTED | 55 |
| Pre-intervention Testing | 55 |
| COMPLETED | 0 |
| NOT COMPLETED | 55 |
Reasons for not completing this period:
| Reason | Web-based Waveform Interpretation Guide |
|---|---|
| lack of resources | 55 |
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 | Web-based Waveform Interpretation Guide |
|---|---|---|
| Participants analysed | 55 | |
| Age, Customized: any age | participants | 55 |
| Sex/Gender, Customized: any gender | participants | 55 |
| Region of Enrollment: United States | participants | 55 |
6. Primary Endpoint
The registry lists the primary outcome as Score on a Computer-based Test on Pulmonary Artery Catheter Waveform Interpretation, measured over 1 month.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was the score on a computer-based test of pulmonary artery catheter waveform interpretation. The planned measurement time was 1 month. A score on an interpretation test is a direct assessment of performance on the task the guide was intended to support. In general, an assessment closely related to the skill of interest can help describe whether participants can apply relevant knowledge in a test setting. That general rationale does not establish how well this particular test represented clinical practice.
The registry does not report the score’s unit, scoring range, scoring rules, or how a score would be interpreted. It also does not describe the test’s content or its measurement properties. Those details are important for judging what a difference in scores would mean, but they are not available in the registry record.
Most importantly, the endpoint was not measured. The study was terminated before the primary outcome could be assessed, and none of the participants took the post-intervention test. There is therefore no posted score, change estimate, uncertainty interval, or test-based comparison to interpret. The endpoint identifies what the investigators intended to measure, not a result demonstrating how participants performed.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The primary outcome cannot be interpreted as an effect estimate because it was not observed. The registry record states that the study ended before the computer-based test outcome could be measured and that no participant took the post-intervention test. It reports no score distribution, average, variability measure, confidence interval, or test of statistical significance for that endpoint. The registry also records 0 analyses.
This absence is not evidence that performance improved, nor is it evidence that performance failed to improve. The results do not permit a conclusion in either direction. In particular, the stated intention to improve interpretation should not be confused with a measured improvement. The trial’s purpose and its outcome evidence are separate: the purpose is described, while the planned primary outcome is unavailable.
The single-group, non-randomized design is also relevant to interpretation. Even if a post-intervention score had been reported, an uncontrolled result would not provide a randomized comparison with participants who did not receive the guide. General statistical reasoning indicates that observed changes in a single group can have explanations other than the intervention. In this record, however, there is no post-intervention score to assess in the first place, so no within-group change can be described.
The secondary outcome concerns individual and collective frequency of use and usage patterns of the guide. Although that outcome is listed, results for it are not reported in the registry record. The listing alone does not show that use was measured, how much the guide was used, or whether use was associated with test performance. Such an association cannot be assessed without the corresponding observations and analyses.
The enrollment entry is 55, but enrollment alone does not show how many participants contributed data to a particular outcome. For the primary endpoint, the record specifically says none took the post-intervention test. There is consequently no observed primary-outcome sample on which to base a statistical estimate. Participant characteristics, exclusions, and other analysis-population details are not reported in the registry record.
The record’s status is terminated, but it does not give a reason for termination. That status provides context for the missing primary endpoint; it does not explain the decision or identify whether other study activities occurred. The statistically appropriate reading is limited: the registry documents a planned assessment and its non-measurement, not an estimated benefit or lack of benefit. Any broader claim about the guide’s effect would go beyond the posted outcome evidence.
9. Statistical Methods Explained
Statistical methods describe how observations are turned into estimates and how uncertainty is assessed. In this record, the primary test outcome was not measured, and 0 analyses are recorded. As a result, there is no reported primary-outcome estimate to interpret and no analysis procedure to evaluate against observed scores. The registry does not report a statistical analysis plan, the intended score summary, or a method for handling outcome data.
What would a score estimate describe?
In general, an estimate summarizes the observed data for a defined group and outcome. For a test score, the choice of summary would depend on the score’s scale and distribution. A mean can describe a group’s average when that is suitable for the measurement; other summaries may be preferable when scores have unusual distributions or meaningful bounds. The scoring scale and distribution are not reported in the registry record, so it is not possible to identify which summary would have been appropriate for this test.
For a change analysis, the observations needed to calculate change must exist at the relevant assessment times. General statistical reasoning distinguishes a measured change from a statement of intended improvement. Here, no participant took the post-intervention test. The record therefore contains no post-intervention scores from which to estimate a change. It also does not report a baseline score or a planned approach to pairing measurements, so no specific before-and-after analysis can be inferred.
How should uncertainty be understood?
In general, a confidence interval gives a range of values compatible with an estimate and its statistical uncertainty under a specified method. It helps show precision: a narrow interval indicates greater precision than a wide interval, while both the interval and the method depend on observed data and assumptions. No confidence interval is reported for the primary outcome, because there is no measured post-intervention test result in the registry record. There is thus no interval from which to judge the precision of an effect estimate.
A p-value, in general, describes how compatible observed data are with a specified null model under the assumptions of a statistical test. It does not measure the size or importance of an effect. No primary-outcome p-value is reported. The registry does not state a planned hypothesis test or the model that would have been used. The significance-level assumption appearing in the record’s sample-size description is a planning assumption; it is not a result of a test of the study outcome.
What does the planning illustration represent?
The registry describes sample-size assumptions as a planning illustration computed from an observed effect, rather than the trial’s own design. The stated assumptions include a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect expressed as a stated fraction of the observed effect. The registry also distinguishes the reporting convention for time-to-event planning from other outcomes. These assumptions describe an illustrative calculation, not an observed analysis of this single-group study.
Such planning calculations are not observed power and do not establish that a trial was adequately designed. They ask, under specified assumptions, what sample size would be associated with a target level of power for a chosen effect. In this case, the primary outcome was not measured and an observed primary-outcome effect is not reported in the registry record. Any illustration that depends on an observed effect should therefore not be read as an empirical estimate of the guide’s effect or as evidence about the trial’s outcome.
Why does over-dispersion matter in general?
Over-dispersion is a general concern when data vary more than a statistical model assumes. If a model understates variability, estimated uncertainty can be too small and inferential conclusions can appear more precise than warranted. Model choice should reflect the type and distribution of the outcome. The registry record does not report a score distribution, a fitted model, or an assessment of over-dispersion, and there are no primary test observations on which to assess it. This concept is relevant to statistical practice generally, not a reported feature of this study’s analysis.
The design also constrains the kind of estimate that could be obtained. In general, a single-group study can describe outcomes within the group, but without a control group it cannot make a randomized comparison between guide access and a separate condition. The registry reports no randomized comparator. Since the primary endpoint is absent, even a descriptive post-intervention estimate cannot be made from the posted results.
10. Multiplicity, Missing Data and Analysis Populations
Multiplicity concerns the interpretation of multiple outcomes, comparisons, or statistical tests. In general, conducting several tests can increase the chance of finding an apparently notable result by chance, so an analysis plan may specify how multiple tests will be handled. This registry lists the primary test-score outcome and a secondary outcome concerning frequency of use and usage patterns. It does not report a multiplicity strategy or analysis plan. Because 0 analyses are recorded and the primary outcome was not measured, there are no reported test results for which multiplicity adjustment can be evaluated.
The main missing-data issue is the absence of the planned post-intervention test. The registry states that termination occurred before the primary outcome could be measured and that none of the participants took that test. This is not a situation in which the record reports some observed test scores and leaves other participants’ scores missing; it reports no post-intervention test-taking. The reason the assessment did not occur is not reported in the registry record.
No imputation method, missing-data model, or sensitivity analysis is reported in the registry record. General methods for handling missing observations depend on why data are missing, what other measurements are available, and the assumptions that can be justified. Those details are not available. Imputing scores would require assumptions and information that are not reported, and no imputed results appear in the posted record.
The record lists enrollment as 55, but does not describe analysis populations or provide participant flow beyond the statement about the post-intervention test. It is therefore not possible to identify a tested population, a completed-test population, or a broader analysis set for the primary outcome. No result for the secondary usage outcome is reported either. The absence of analysis and outcome data limits both efficacy interpretation and assessment of how missingness was handled.
11. What the Result Does, and Does Not, Mean
The posted record establishes that the study was intended to assess a web-based guide for PAC waveform interpretation and that the planned primary outcome was a computer-based test score at 1 month. It also establishes that the study was terminated before the outcome could be measured and that none of the participants took the post-intervention test. These are the central details for interpreting the study statistically.
The record does not establish whether the guide improved interpretation, had no effect, or affected performance in another way. No primary test scores or analysis are reported. The missing outcome is not a result showing no difference; it is an outcome that was not measured. Nor does the study’s stated goal establish that the guide achieved that goal.
Because the study is single-group and non-randomized, it does not provide a randomized control comparison. General statistical interpretation would treat that as an important design limitation even if outcomes were available. Here, no measured primary result is available to describe within the group, either. The secondary usage outcome is listed but has no reported result in the registry record.
The registry record also does not explain why the study was terminated, describe the test’s scoring system, or report the statistical analysis plan. Those omissions limit the ability to assess the intended measurement and analysis. They do not justify filling in an unreported result or inferring a reason for the study’s status. The evidence supports a narrow conclusion: the planned primary assessment is unavailable in the posted record, so the effectiveness question remains unanswered by these results.
12. Why This Trial Matters Statistically
This trial illustrates an important distinction between a research question and evidence that can answer it. The registry describes a plausible educational objective: assessing whether a web-based guide can support interpretation of PAC waveforms. But a stated objective is not an outcome finding. The trial’s planned score would have been relevant to that question, while the absence of the score prevents an estimate of performance after access to the guide.
Statistically, this matters because estimation requires observed data. Without post-intervention test results, there is no estimate to pair with a confidence interval, no variability to characterize, and no inferential test to interpret. A study can have a recorded enrollment and a defined endpoint yet still provide no analyzable evidence for that endpoint when measurement does not take place.
The study also highlights the limits of a single-group design for causal interpretation. General statistical reasoning distinguishes observing an outcome after an intervention from estimating the effect attributable to that intervention. A randomized comparator can help address that distinction, whereas this record describes no randomized comparison. In this trial, the design limitation is compounded by the missing primary measurement.
Finally, the record makes clear why status and results should be read separately. The study is marked terminated, and the primary outcome is explicitly reported as unmeasured. Neither fact supplies an estimate of the guide’s effect. For researchers and clinicians reading registry evidence, the important statistical lesson is to distinguish a planned endpoint, a completed measurement, and an analyzed result. Only the first is present for the primary endpoint in this record.
13. 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 most direct limitation is that the primary endpoint was not measured. The registry record says the study was terminated before the computer-based test outcome could be collected and that none of the participants took the post-intervention test. Without that measurement, there is no primary result, no estimate of its precision, and no basis for judging the direction or size of any change.
The design is recorded as single-group and non-randomized, with no masking. A separate randomized control group is not reported, so the study was not set up as a like-for-like randomized comparison. The absence of a post-intervention result means that even a within-group description of test performance is unavailable; it also prevents assessment of whether any observed change might have alternative explanations.
The registry does not report why the trial was terminated. It does not describe the test’s scoring scale, the assessment content, participant characteristics, or analysis populations. It also does not report a statistical analysis plan, methods for handling missing outcomes, or results for the listed usage-pattern outcome. These gaps limit assessment of measurement quality, participant flow, and analysis decisions. They should be treated as unreported information rather than grounds for assumptions about the protocol or the reasons for termination.
Although enrollment is listed as 55, that figure does not supply an outcome sample when no participant took the primary post-intervention test. Enrollment should not be treated as the number with analyzed endpoint data. The record’s planning assumptions also do not replace outcome evidence: a planning illustration is not an observed effect or an analysis of this study’s primary endpoint.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: Effectiveness of a Computer Application in Improving Pulmonary Artery Catheter Waveform Interpretation — NCT00138073.
- Registry record last updated 2014-06-30; status last verified 2014-05.
- Results first posted 2014-06-30.
- 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.
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17. Record Summary
NCT00138073 is a terminated, single-group, non-randomized study of a web-based guide for pulmonary artery catheter waveform interpretation among nurses and physicians. Enrollment is recorded as 55, and the study has no masking. The primary endpoint was a computer-based interpretation test score measured at 1 month. The registry record states that the study ended before the endpoint was measured and that none of the participants took the post-intervention test.
The record lists guide-use frequency and usage patterns as a secondary outcome, but does not report its results. It records 0 analyses. No primary test result is available, so the registry cannot establish whether performance changed after access to the guide. The reason for termination and further details of the planned statistical analysis are not reported in the registry record.