Talk to the Veterans Crisis Line now
U.S. flag
An official website of the United States government

VA Health Systems Research

Go to the VA ORD website
Go to the QUERI website

HSR Citation Abstract

Search | Search by Center | Search by Source | Keywords in Title

Benchmarking physical therapy clinic performance: statistical methods to enhance internal validity when using observational data.

Resnik L, Liu D, Hart DL, Mor V. Benchmarking physical therapy clinic performance: statistical methods to enhance internal validity when using observational data. Physical Therapy. 2008 Sep 1; 88(9):1078-87.

Dimensions for VA is a web-based tool available to VA staff that enables detailed searches of published research and research projects.

If you have VA-Intranet access, click here for more information

VA staff not currently on the VA network can access Dimensions by registering for an account using their VA email address.
   Search Dimensions for VA for this citation
* Don't have VA-internal network access or a VA email address? Try searching the free-to-the-public version of Dimensions


Many clinics and payers are beginning programs to collect and interpret outcomes related to quality of care and provider performance (ie, benchmarking). OUTCOMES: assessment is commonly done using observational research designs, which makes it important for those involved in these endeavors to appreciate the underlying challenges and limitations of these designs. This perspective article discusses the advantages and limitations of using observational research to evaluate quality of care and provider performance in order to inform clinicians, researchers, administrators, and policy makers who want to use data to guide practice and policy or critically appraise observational studies and benchmarking efforts. Threats to internal validity, including potential confounding, patient selection bias, and missing data, are discussed along with statistical methods commonly used to address these limitations. An example is given from a recent study comparing physical therapy clinic performance in terms of patient outcomes and service utilization with and without the use of these methods. The authors demonstrate that crude differences in clinic outcomes and service utilization tend to be inflated compared with the differences that are statistically adjusted for selected threats to internal validity. The authors conclude that quality of care measurement and ranking procedures that do not use similar methods may produce findings that may be misleading.

Questions about the HSR website? Email the Web Team

Any health information on this website is strictly for informational purposes and is not intended as medical advice. It should not be used to diagnose or treat any condition.