What is the difference between clinical significance and st…

What is the difference between clinical significance and statistical significance? How might these concepts be applied to program evaluation? Give an example of an instance in which you might be torn between two types of significance in the reported results of research. What are some other types of statistical evaluations that help to sort out the true significance of clinical research findings? Provide at least two scholarly references for your discussion and justifications.


In the realm of research and program evaluation, understanding the difference between clinical significance and statistical significance is paramount. While both concepts aim to inform the interpretation of research findings, they are distinct in their nature and implications. Clinical significance refers to the practical or real-world importance of a research finding, whereas statistical significance concerns the probability that an observed effect is not due to chance. This paper will explore the differences between these two concepts, their application in program evaluation, provide an example that highlights the dilemma between the two types of significance, and discuss additional statistical evaluations that help determine the true significance of clinical research findings.

Clinical Significance vs Statistical Significance:

Clinical significance pertains to the practical importance of research findings in relation to their real-world impact. It focuses on the extent to which the observed effect has meaningful and tangible consequences for individuals or populations. Clinical significance takes into consideration factors such as the magnitude of the effect, the potential benefits or harms of an intervention, and the context in which the findings apply. In essence, it addresses whether the observed effect is relevant and clinically meaningful in terms of its potential to improve outcomes or inform decision-making.

On the other hand, statistical significance is concerned with the likelihood that an observed effect is not due to chance. It is based on mathematical calculations that determine whether the differences or associations observed in a study are likely to be representative of the broader population. Statistical significance assesses the presence of an effect by comparing the observed data to a null hypothesis, which assumes that no true effect exists. If the p-value falls below a predetermined threshold (usually 0.05), researchers infer that the observed effect is statistically significant, suggesting that it is unlikely to have occurred by chance alone.

Application of Clinical and Statistical Significance in Program Evaluation:

Program evaluation involves assessing the effectiveness and impact of interventions, policies, or programs. Both clinical and statistical significance play crucial roles in such evaluations. Clinical significance is relevant in determining whether the observed effects of a program are practically meaningful and beneficial. For example, in evaluating a smoking cessation intervention, clinical significance would involve assessing whether the effect of the program on smoking cessation rates is sufficient to reduce the risk of smoking-related diseases.

Statistical significance, on the other hand, helps ensure that observed effects are not merely due to chance. In program evaluation, statistical significance allows us to make conclusions about the program’s effectiveness that go beyond the specific sample under study. It provides evidence that the observed effects are likely to be replicated in the broader population. Therefore, assessing statistical significance aids in determining whether the observed effects are reliable and generalizable.

Example of Dilemma between Clinical and Statistical Significance:

To illustrate the dilemma between clinical and statistical significance, consider a study evaluating the effectiveness of a new drug for reducing blood pressure. The study finds a statistically significant reduction in blood pressure measurements among the treatment group compared to the control group. However, although statistically significant, the observed effect is relatively small, resulting in only a minor decrease in blood pressure.

In this scenario, there is a conflict between clinical significance and statistical significance. The statistical analysis indicates that the effect of the drug is unlikely to be due to chance, supporting the claim that it has an effect. However, from a clinical standpoint, the small magnitude of the effect raises questions about its relevance and practical importance. Despite being statistically significant, the observed effect may not be clinically significant if the reduction in blood pressure does not lead to meaningful improvements in health outcomes or quality of life for patients.

Additional Statistical Evaluations:

In addition to assessing statistical significance, there are several other statistical evaluations that help ascertain the true significance of clinical research findings. These evaluations include effect size calculations, confidence intervals, and replication studies.

Effect size calculations quantitatively measure the magnitude of an observed effect. By comparing the effect size to known benchmarks or meaningful thresholds, researchers can determine the practical importance of the effect. For instance, in a study evaluating a psychological intervention, effect size calculations can help determine whether the observed improvement in symptoms is substantial enough to make a meaningful difference in patients’ mental health.

Confidence intervals provide a range of values within which the true population parameter is likely to fall. They offer additional information beyond the point estimate provided by the p-value and can help assess the precision and reliability of the observed effect. Wide confidence intervals suggest uncertainty in the estimated effect size, while narrow intervals indicate greater precision.

Replication studies involve repeating the original study to confirm the findings. Replication studies are essential for ensuring the generalizability and robustness of research findings. By conducting multiple independent studies that yield similar results, researchers can enhance confidence in the clinical and statistical significance of their findings.


In conclusion, clinical significance and statistical significance are distinct concepts that serve different purposes in research and program evaluation. While clinical significance addresses the practical importance of research findings, statistical significance evaluates the likelihood that observed effects are not due to chance. Both concepts are essential in program evaluation, where clinical significance informs the real-world impact of interventions, and statistical significance ensures the reliability and generalizability of the observed effects. Assessing additional statistical evaluations such as effect size, confidence intervals, and replication studies can further enhance our understanding of the true significance of clinical research findings.