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 Group CBT for Aggression in Veterans (NCT02233517), a randomized na study. The primary outcome is Change in Mean Scores on the Conflicts Tactics Scale (CTS) From Baseline to Post-treatment, 3 Month and 6 Month Follow-up..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02233517 |
| Phase | NA |
| Condition | Aggression, Anger, Posttraumatic Stress Disorder |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 66 |
| Arms in the primary outcome | n/a |
| Lead sponsor | VA Office of Research and Development |
| Results posted | Yes |
2. Clinical Question
The trial asks whether group cognitive behavioral therapy for anger and aggression differs from present-centered therapy on physically aggressive behaviors among veterans with PTSD. The primary outcome is change in mean Conflicts Tactics Scale scores from baseline to post-treatment and follow-up. The registry record describes assessments at post-treatment, 3 months post-treatment, and 6 months post-treatment.
Population
Veterans with PTSD enrolled in a study of group treatment for anger and aggression. The primary-outcome description says 36 participants were assigned to groups and describes analyses of 35 participants’ data after data screening. The overall enrollment is 66.
Intervention
Cognitive-Behavioral Therapy for Anger and Aggression in Combat Veterans with PTSD, described as a manualized group treatment protocol. The registry record describes it as a 12-week treatment.
Comparator
Present Centered Therapy, described as an active, manualized comparison condition for psychotherapy trials.
Primary question
How do mean scores on the Conflicts Tactics Scale change from baseline through post-treatment and follow-up in the two assigned groups? The registry record does not report the numerical results needed to describe the size or precision of the between-group difference.
The comparison is relevant to the trial’s stated focus on anger and aggression in veterans with PTSD. The registry’s background describes functional impairment associated with PTSD-related anger and aggression and identifies treatment as an area of interest. Those statements explain the study rationale; they are not evidence of the trial’s outcome. The result needed to answer the clinical question—an estimated contrast between the assigned groups, with its uncertainty—is not reported in the registry record.
3. Trial Design
This was a randomized, parallel-group trial with no masking. The registry lists the phase as not applicable and records an overall enrollment of 66. The study status is completed. The listed sponsor is the VA Office of Research and Development. The study start date is 2015-02-09, and the primary completion date is 2017-07-05.
The two behavioral interventions were Cognitive Behavioral Therapy and Present Centered Therapy. The former is described as a 12-week manualized group treatment for anger and aggression in combat veterans with PTSD. The latter is described as an active, manualized psychotherapy comparison condition intended to control for nonspecific features of therapy, such as therapist contact, treatment rationale, and expectations of therapeutic benefit. The record does not report enough detail to characterize how treatment sessions were delivered or how adherence to the manuals was assessed.
Random allocation is stated, but the method used to generate the allocation sequence, the approach to conceal allocation, and the allocation ratio are not reported in the registry record. No masking was used. The record does not report whether outcome assessors or analysts were masked.
The primary outcome concerns mean Conflicts Tactics Scale scores at baseline, post-treatment, 3 months post-treatment, and 6 months post-treatment. Its listed timeframe also gives the post-treatment and follow-up weeks. The registry lists secondary outcomes concerning community reintegration, disability, psychosocial functioning, and family assessment. It reports 11 outcome measures and 27 analyses, but does not give a complete account of how those analyses relate to each outcome or time point.
The overall enrollment and the primary-outcome analysis population are different quantities. The primary description says 36 participants were assigned to groups and reports that 35 participants’ data were analyzed after screening. The record does not reconcile those figures with the overall enrollment of 66, so they should not be treated as interchangeable counts. The protocol, sample-size justification, interim-analysis plan, and complete 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.
Before assignment: 30 participants were excluded after enrollment: 13 did not meet inclusion criteria; 17 declined to participate or were lost to contact.
Overall Study
| Stage | Cognitive Behavioral Therapy | Present Centered Therapy |
|---|---|---|
| STARTED | 19 | 17 |
| COMPLETED | 12 | 13 |
| NOT COMPLETED | 7 | 4 |
Analysis population for the primary outcome, as defined in the registry: Last observation carried forward analyses used; 36 participants assigned to groups. Data screening found one participant's data (male, CBT arm) were not valid; 35 participants' data analyzed. One participant (male, PCT arm) contacted, confirmed that 3 month data was invalid; data for this subject, this time point, this measure not used.
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 | Cognitive Behavioral Therapy | Present Centered Therapy | Total |
|---|---|---|---|---|
| Participants analysed | 19 | 17 | 36 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 16 | 13 | 29 |
| Age, Categorical: >=65 years | Participants | 3 | 4 | 7 |
| Age, Continuous | years | 50.8 (SD 11.7) | 52.6 (SD 12.3) | 51.6 (SD 11.9) |
| Sex: Female, Male: Female | Participants | 5 | 6 | 11 |
| Sex: Female, Male: Male | Participants | 14 | 11 | 25 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 | 1 | 1 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 19 | 16 | 35 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| 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 | 11 | 10 | 21 |
| Race (NIH/OMB): White | Participants | 7 | 7 | 14 |
| Race (NIH/OMB): More than one race | Participants | 1 | 0 | 1 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Region of Enrollment: United States | Participants | 19 | 17 | 36 |
6. Primary Endpoint
The registry lists the primary outcome as Change in Mean Scores on the Conflicts Tactics Scale (CTS) From Baseline to Post-treatment, 3 Month and 6 Month Follow-up., measured over pre-treatment (baseline), post-treatment (12 weeks), 3 months post-treatment (48 weeks), and 6 months post-treatment (84 weeks).
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change in the mean score on the Conflicts Tactics Scale (CTS), measured from baseline to post-treatment, 3 months post-treatment, and 6 months post-treatment. The scale concerns physically aggressive behaviors during the past 30 days. Examples in the registry description include throwing something at someone, pushing, grabbing, shoving, slapping, kicking, biting, hitting, beating someone up, threatening someone with a gun or knife, or using a gun or knife on someone.
The registry describes a scale range from 0, meaning never, to 6, meaning more than 20 times. The outcome is a continuous measure summarized by a mean and standard deviation. This kind of score can describe the average reported frequency across a group, while the distribution of individual scores may vary around that average. A change in the mean therefore does not show how every participant’s score changed.
The measure is used to assess the behavior that the study is intended to address: physically aggressive acts. Repeated measurement after treatment can describe whether the group averages differ over the specified assessment periods. However, the registry record does not report the mean scores, changes, between-group contrasts, or uncertainty estimates. Consequently, the measure’s definition is available, but the direction, magnitude, and precision of the observed outcome are not.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a randomized comparison and a relevant behavioral outcome, but it does not include the numerical primary-outcome results. It is therefore not possible to describe whether either group had a higher or lower mean CTS score, how the means changed over time, or how large the difference between the assigned groups was. The record also does not report a confidence interval or a primary-outcome test result. Without those quantities, neither the magnitude nor the statistical precision of the primary comparison can be assessed.
The analysis population description says that last observation carried forward analyses were used. It also says that 36 participants were assigned to groups, that screening found one participant’s data in the CBT arm were not valid, and that 35 participants’ data were analyzed. A further note concerns one participant in the PCT arm whose 3-month data were confirmed as invalid. The remaining sentence describing the handling of that participant’s data is incomplete in the registry record. These details indicate that the analysis did not simply use every recorded observation without qualification, but they do not establish exactly how every outcome and time point was handled.
The record lists 11 outcome measures and 27 analyses, and the primary outcome includes repeated assessment periods. That context matters when interpreting statistical findings: multiple outcomes, time points, or contrasts can create more than one opportunity to observe a nominally unusual result. Whether the investigators adjusted for multiplicity, selected a primary contrast in advance, or followed a prespecified testing sequence is not reported in the registry record. No particular adjustment or testing strategy should be assumed.
The trial’s randomization supports interpretation of the assigned-group comparison as a randomized comparison, but randomization alone does not supply the missing outcome estimates. The record does not report the allocation procedure or a full account of the analysis population, and the no-masking design may be relevant to how subjective reports are collected or interpreted. These considerations do not establish that bias occurred; they identify information needed to evaluate the evidence more fully.
The planning illustrations use the observed effect as a basis for sample-size calculations, with a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. Their purpose is planning, not a report of observed power. The specific planning estimates and the effect fractions are not included in the registry entries described for this analysis, and the record does not report the trial’s own sample-size justification. No conclusion about achieved power or adequacy of sample size follows from those planning assumptions.
In short, the registry record establishes the question, design, outcome scale, and some information about data handling. It does not provide the outcome estimates required to judge the size or precision of the treatment contrast. The available record therefore supports a description of what was planned and how the endpoint was defined, but not a quantitative interpretation of the primary result.
9. Statistical Methods Explained
The trial is described as randomized and parallel-group, with no masking. General statistical interpretation begins by distinguishing assignment from outcome measurement: randomization concerns how participants are allocated, while the CTS records reported behavior over a specified period. The registry does not report the procedure used to generate or conceal the allocation sequence, so those design details cannot be assessed from the registry record.
What does a mean score describe?
The primary outcome is a mean on a continuous scale. A mean summarizes the scores in a group, but does not show the spread of scores or the pattern for each participant. The registry identifies standard deviation as the measure of dispersion. In general, a standard deviation describes how dispersed observations are around a mean. It is not itself an estimate of the uncertainty in a group mean or in a between-group contrast.
The CTS is described as a frequency scale for physically aggressive behaviors during the past 30 days, ranging from 0 (never) to 6 (more than 20 times). Because a mean compresses individual scores into a group summary, it can conceal variation in the types or frequency of reported behavior. The registry record does not report the distribution of individual scores, so that variation cannot be evaluated from the endpoint description alone.
What would a between-group estimate show?
In general, a between-group estimate expresses the difference in an outcome between the assigned groups, according to a specified analysis. A confidence interval gives a range of values compatible with the data and the analysis assumptions; a narrower interval indicates greater precision than a wider one. A significance test addresses compatibility with a specified null hypothesis under its assumptions. Neither a test result nor an interval, by itself, explains the importance of a difference in practical terms.
For this trial, numerical group means, a between-group estimate, a confidence interval, and a test result for the primary outcome are not reported in the registry record. The general meaning of those statistics cannot substitute for the missing trial estimates. No conclusion about statistical significance or precision can be drawn without them.
How should repeated assessments be considered?
The primary outcome is assessed at baseline, post-treatment, 3 months post-treatment, and 6 months post-treatment. In general, repeated observations on the same participant are related rather than independent. An analysis of repeated measurements needs to account for that dependence or specify how the observations are reduced to a particular contrast. The registry describes change in mean scores over the assessment periods, but does not report the model, covariance structure, contrast definition, or other details of the primary analysis. The analysis method for the repeated measurements is therefore not reported in the registry record.
The primary outcome description says that last observation carried forward analyses were used. In general, this method substitutes a participant’s last recorded value for a later value that is missing. It can produce a complete-looking analysis dataset, but it relies on an assumption that carrying the last observed value forward is a suitable representation of the unobserved value. That assumption may not hold if the outcome changes over time. The registry does not report a sensitivity analysis that would show how conclusions change under alternative missing-data assumptions.
Why does over-dispersion matter?
Over-dispersion is a general issue in data where observed variation is greater than a model assumes. When a model understates variability, standard errors can be too small and confidence intervals too narrow. The CTS is described as a continuous mean outcome with a standard deviation, but the registry does not report a model or diagnostics that would establish whether over-dispersion was assessed or relevant to the primary analysis. It would therefore be inappropriate to claim that the analysis used a method to address it.
More generally, the scale’s bounded frequency categories and the averaging of participant scores make it important to understand the distribution and the chosen model. The record does not report distributional checks, transformations, robust variance methods, or other modeling decisions. These are examples of information that can help readers assess assumptions; they are not claims that any particular method was required or used in this trial.
What are the sample-size figures for?
General sample-size illustrations can estimate how many participants per arm would be needed to detect a stated fraction of an observed effect under specified assumptions. The registry describes its planning illustration as using a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. Such calculations are conditional on the assumptions and the effect used for planning. They are not observed power, and they do not show the probability that the completed trial detected its true effect.
The registry states that the effect to detect is a stated fraction of the observed effect. The actual planning estimates and effect fractions are not reported in the registry record for this analysis. The trial’s own design rationale and sample-size justification are also not reported in the registry record. The planning assumptions should not be read as proof that those assumptions formed the original protocol plan.
What does the registry report about multiplicity?
Multiplicity concerns the number of statistical questions addressed, such as tests across multiple outcomes, time points, or contrasts. In general, conducting multiple tests without an appropriate strategy can increase the chance of at least one apparently notable result under a null hypothesis. The registry lists 11 outcome measures and 27 analyses, while the primary endpoint itself includes multiple assessment periods. It does not report whether multiplicity was controlled, how the primary contrast was selected, or whether analyses were prespecified. Consequently, the registry record does not support a claim that a particular multiplicity method was used.
The registry’s description of the primary analysis is incomplete after its account of invalid data in the PCT arm. Other details—including the full analysis model, treatment of every missing value, and the mapping between analyses and outcomes—are not reported in the registry record. These gaps limit reproducibility and interpretation, independently of the general statistical principles.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 11 outcome measures and 27 analyses. The primary outcome has repeated assessments at baseline, post-treatment, 3 months post-treatment, and 6 months post-treatment. In general, multiple outcomes and time-point comparisons raise multiplicity questions: readers need to know which comparisons were primary and whether the analysis plan accounted for the number of tests. The registry record does not report a multiplicity adjustment, a hierarchy of outcomes, or a prespecified testing sequence. It also does not provide enough detail to determine which of the 27 analyses correspond to which outcomes and contrasts.
For missing data, the primary-outcome description states that last observation carried forward analyses were used. It says 36 participants were assigned to groups, that screening found one participant’s data in the CBT arm were not valid, and that 35 participants’ data were analyzed. It also reports that one participant in the PCT arm was contacted and confirmed that 3-month data were invalid. The sentence describing the subsequent handling of that participant’s data is incomplete in the registry record. The record does not fully specify missingness at each assessment, reasons for all unavailable data, or sensitivity analyses.
The outcome description therefore gives some information about exclusions and imputation, but not a complete account of the analysis populations. The overall enrollment is 66, while the primary description refers to 36 participants assigned to groups and 35 participants’ analyzed data. The registry does not reconcile these counts. The protocol-defined analysis population, intention-to-treat status, and any per-protocol population are not reported in the registry record.
In general, missing-data methods rely on assumptions about why values are absent and what unobserved values might have been. Last observation carried forward makes a specific substitution; it does not remove the need to consider those assumptions. Without a complete description or sensitivity analyses, the robustness of the primary analysis to missing-data choices cannot be assessed.
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 |
|---|---|---|---|
| Cognitive Behavioral Therapy | 2 | 19 | 10.5% |
| Present Centered Therapy | 1 | 17 | 5.9% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Cognitive Behavioral Therapy | 0 of 19 |
| Present Centered Therapy | 0 of 17 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Cognitive Behavioral Therapy | 0 of 19 |
| Present Centered Therapy | 0 of 17 |
Most frequent serious adverse event terms
| Event term | Organ system | Cognitive Behavioral Therapy | Present Centered Therapy |
|---|---|---|---|
| Diagnosed with cancer | Respiratory, thoracic and mediastinal disorders | 1 of 19 | 0 of 17 |
| Hospitalization | Respiratory, thoracic and mediastinal disorders | 0 of 19 | 1 of 17 |
| Hospitalization | Eye disorders | 1 of 19 | 0 of 17 |
Serious events with the highest arm-level rate: hospitalization (5.9%), diagnosed with cancer (5.3%).
The registry reports serious adverse events and other adverse events separately for the two groups. For Cognitive Behavioral Therapy, 2 of 19 participants at risk were reported as having a serious adverse event; no participants were reported with other adverse events, and deaths were 0. For Present Centered Therapy, 1 of 17 participants at risk was reported as having a serious adverse event; no participants were reported with other adverse events, and deaths were 0. These are the counts recorded in the registry, not estimates of the treatment effect on safety.
The registry also lists “Hospitalization” at 5.9% and “Diagnosed with cancer” at 5.3% among the top serious terms. It does not explain in the available record how those percentages relate to participants, events, or the group-specific counts. They should therefore be read as reported terms and percentages, not converted into additional arm-specific event rates.
In general, adverse-event counts depend on the period of observation, definitions, ascertainment, and completeness of reporting. Those details are not fully described in the registry entries for this trial. The denominators shown are participants at risk in each group; the counts do not, on their own, establish causation or support a comparative safety estimate. No deaths are reported in either group.
12. What the Result Does, and Does Not, Mean
The record describes a randomized comparison of group cognitive behavioral therapy for anger and aggression with present-centered therapy in veterans with PTSD. It identifies physically aggressive behavior, measured with the CTS, as the primary outcome and gives the scale’s range and assessment periods. It also records that the trial was completed and reports some details about the primary analysis population and adverse events.
What the record does not provide is the numerical primary-outcome result. There are no group means or mean changes, no between-group estimate, and no confidence interval or test result in the registry entries. It is therefore not possible to state whether the outcome favored either group, to quantify the size of any contrast, or to judge its precision. This absence is not evidence that the groups were the same; it means the registry record does not report the result needed to make that assessment.
Even when a numerical difference is reported, general statistical interpretation distinguishes the estimated effect from its uncertainty and from its practical meaning. A confidence interval describes precision under an analysis; statistical significance does not by itself establish importance. Conversely, lack of a statistically significant result does not by itself demonstrate equivalence. The registry record does not report an equivalence or noninferiority framework, and no such conclusion should be inferred.
The sample-size illustrations are planning calculations based on the observed effect and stated assumptions. They are not observed power and do not replace the trial’s primary estimate. The record does not report the trial’s own sample-size justification. Likewise, the adverse-event counts are descriptive registry entries and do not establish that an event was caused by treatment or that one group had a different safety profile.
The most defensible reading is therefore limited: the registry identifies the intended comparison, outcome, and some analysis and safety information, but lacks the quantitative primary results required for a conclusion about the observed treatment contrast. A fuller interpretation would require the reported outcome estimates, uncertainty, complete analysis methods, and clearer accounting of participants and missing data.
13. Why This Trial Matters Statistically
This trial is statistically informative as an example of why a registry description and a quantitative results report answer different questions. The record defines a randomized, parallel-group comparison and specifies a behavioral endpoint, the CTS, including the recall period and scale range. Those details help clarify what was intended to be measured. They do not reveal the observed difference between groups.
The primary outcome is measured repeatedly, and the registry lists multiple outcomes and analyses. This makes clarity about the primary contrast, analysis model, missing-data approach, and multiplicity strategy important. The record reports last observation carried forward and some data-screening decisions, but its account of the PCT participant’s invalid 3-month data ends before the handling is fully explained. It also does not report whether multiplicity was addressed or how the listed analyses were organized.
The enrollment figures illustrate why population definitions should be explicit. Overall enrollment is 66, while the primary-outcome description refers to 36 participants assigned to groups and 35 participants’ data analyzed. Those numbers refer to information in different parts of the record, and the record does not reconcile them. Without a clear flow of participants from enrollment through analysis, readers cannot fully evaluate which observations contribute to the endpoint.
Finally, planning calculations should be distinguished from results. The stated planning assumptions concern sample-size illustrations; they do not establish observed power or explain the trial’s original design choices. The registry’s lack of primary effect estimates means that statistical precision cannot be judged. Together, these features show the value of complete reporting: a defined endpoint and randomized design are necessary context, while estimates, uncertainty, analysis details, and participant accounting are needed to interpret the evidence.
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 registry record is that it does not report numerical results for the primary CTS outcome. Mean scores, changes, between-group estimates, confidence intervals, and test results are not available in the registry record for this analysis. The outcome’s direction, magnitude, and precision therefore cannot be evaluated.
The description of the primary analysis population is incomplete. It states that last observation carried forward analyses were used, identifies invalid data for one participant in the CBT arm, and notes invalid 3-month data for one participant in the PCT arm. The description ends before fully explaining how the latter data were handled. It does not give a complete participant flow or reconcile the 36 assigned and 35 analyzed figures with the overall enrollment of 66.
The statistical analysis plan is not reported in sufficient detail to assess the model for repeated measurements, the definition of the primary contrast, the handling of all missing observations, or the assumptions used. Sensitivity analyses are not reported. The registry also does not state whether multiplicity was addressed, despite listing 11 outcome measures and 27 analyses and specifying multiple primary-outcome assessment periods.
Design information is also limited. The record identifies randomization and no masking, but does not report the allocation-generation or concealment procedures, whether outcome assessors or analysts were masked, or the protocol’s sample-size justification. The planning assumptions do not fill that gap. The safety entries provide counts and top serious terms, but the available record does not fully explain the relationship between the term percentages and group-specific event counts. These limitations concern reporting and interpretability; they do not establish that a particular bias or analysis problem occurred.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Group CBT for Aggression in Veterans — NCT02233517.
- Registry record last updated 2019-05-31; status last verified 2019-05.
- Results first posted 2019-05-31.
- 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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18. Record Summary
NCT02233517 is a completed randomized, parallel-group trial with no masking, sponsored by the VA Office of Research and Development. It enrolled 66 participants and compared group Cognitive Behavioral Therapy for Anger and Aggression in Combat Veterans with PTSD with Present Centered Therapy. The registry describes the primary outcome as change in mean CTS score from baseline through post-treatment and follow-up.
The CTS measures physically aggressive behaviors over the past 30 days on a scale from 0 (never) to 6 (more than 20 times). The primary-outcome description reports last observation carried forward analyses and notes data-screening concerns, but does not fully describe all data handling. The registry lists 11 outcome measures and 27 analyses. Numerical primary-outcome results and the complete statistical analysis plan are not reported in the registry record, so the primary contrast and its precision cannot be assessed.