Physical therapist using confidence intervals to guide treatment.

Decoding Confidence Intervals: Are You Missing This Vital Sign in Physical Therapy?

Jordan Keane in Health & Wellness December 2025 • 4 min read.

"A deep dive into why understanding confidence intervals is crucial for making informed decisions about treatment options and how it's becoming a must-have skill for today's therapists."

In the rapidly evolving world of healthcare, evidence-based practice has become the gold standard. For physical therapists, this means critically evaluating research to determine the best course of action for their patients. But navigating the sea of clinical trials and statistical analyses can be daunting. A key skill? Understanding and interpreting confidence intervals.

Traditionally, physical therapy research has relied heavily on p-values to determine the significance of treatment effects. However, p-values alone don't tell the whole story. They offer limited insight into the magnitude and clinical relevance of a treatment's impact, leaving therapists with an incomplete picture.

Enter confidence intervals: a powerful tool for assessing the precision and reliability of research findings. Unlike p-values, confidence intervals provide a range within which the true treatment effect is likely to lie, giving therapists a more nuanced understanding of the potential benefits and risks. But are confidence intervals widely used and understood in the field of physical therapy? A recent study sheds light on this crucial question.

The Confidence Interval Gap: What the Research Reveals

Physical therapist using confidence intervals to guide treatment.

A comprehensive analysis of 200 randomized controlled trials (RCTs) in physical therapy, drawn from the Physiotherapy Evidence Database (PEDro), revealed a surprising trend: less than one-third of these trials reported confidence intervals for between-group comparisons. This means a significant portion of research may be lacking a critical component for informed decision-making.

The study, which examined trials from 1986, 1996, 2006, and 2016, highlighted that while the overall prevalence of confidence interval use was only 29%, there's a silver lining: a consistent increase in reporting over time. This suggests a growing awareness of their importance within the physical therapy community.

Funding Matters: Trials that received funding were more likely to report confidence intervals.
Geography Plays a Role: Research conducted in Europe and Oceania showed a higher prevalence of confidence interval use.
Quality Counts: Higher quality trials, as measured by the PEDro scale, were also more likely to include confidence intervals.

These findings underscore the need for greater emphasis on confidence intervals in physical therapy research and practice. But why are they so important, and how can therapists bridge the confidence interval gap?

Bridging the Gap: A Call to Action for Physical Therapists

The study's authors emphasize the critical need for physical therapists to develop a strong understanding of confidence intervals. As their use becomes more prevalent in high-quality research, therapists must be equipped to interpret and apply them effectively in clinical practice.

So, what steps can therapists take to enhance their understanding and utilization of confidence intervals? Start by seeking out educational resources, attending workshops, and engaging in critical appraisal of research articles. Familiarize yourself with online tools and calculators that simplify the interpretation process.

By embracing confidence intervals, physical therapists can move beyond the limitations of p-values and make more informed, evidence-based decisions that ultimately improve patient outcomes. It's time to make confidence intervals a vital sign in the physical therapy profession.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.bjpt.2018.10.004, Alternate LINK

Title: Use Of 95% Confidence Intervals In The Reporting Of Between-Group Differences In Randomized Controlled Trials: Analysis Of A Representative Sample Of 200 Physical Therapy Trials

Subject: Rehabilitation

Journal: Brazilian Journal of Physical Therapy

Publisher: Elsevier BV

Authors: Ana Paula Coelho Figueira Freire, Mark R. Elkins, Ercy Mara Cipulo Ramos, Anne M. Moseley

Published: 2019-07-01

Everything You Need To Know

What are confidence intervals, and how do they work?

Confidence intervals are ranges that suggest where the true treatment effect likely resides. Unlike p-values, which primarily indicate statistical significance, confidence intervals offer a more detailed understanding of the possible benefits and risks associated with an intervention. Interpreting the range of a confidence interval allows therapists to better assess the precision and reliability of research findings related to treatment options.

Why are confidence intervals so important in physical therapy?

Evidence-based practice in physical therapy relies heavily on the critical evaluation of research to determine the best courses of action for patients. Confidence intervals are crucial tools in this context because they provide more comprehensive information than p-values, guiding therapists toward making better-informed decisions. Understanding confidence intervals ensures that physical therapists are using the most reliable research to guide their interventions.

What's wrong with only using p-values?

P-values alone don't provide the complete picture. They only offer a limited view of the impact of a treatment. Confidence intervals, however, reveal a range where the real treatment effect is likely to be. This offers a more nuanced understanding of a treatment's potential and is important because it helps therapists gauge the precision of the research findings. The use of confidence intervals allows for a better assessment of both the potential benefits and risks associated with the treatment, thus leading to better-informed clinical decision-making.

How common are confidence intervals in physical therapy research?

A study analyzing 200 randomized controlled trials (RCTs) in physical therapy from the Physiotherapy Evidence Database (PEDro) revealed that less than one-third reported confidence intervals for between-group comparisons. This finding suggests that a significant amount of research might be missing a critical component for informed decision-making. However, it also showed that there's a consistent increase in reporting over time, indicating growing awareness of their importance within the physical therapy community.

What factors influence the use of confidence intervals?

The findings suggest that trials with funding, those conducted in Europe and Oceania, and higher quality trials, as measured by the PEDro scale, are more likely to report confidence intervals. This underscores the need for physical therapists to deepen their understanding of confidence intervals. This understanding is key as confidence intervals are becoming more prevalent in high-quality research, and therapists must be equipped to interpret them effectively in practice to improve patient care and treatment outcomes.