In 2019, the Psychometrics Special Interest Group (SIG) developed a collection of papers that was published in the Journal of Patient-Reported Outcomes (JPRO). The set of papers originated from SIG members discussing different approaches to analyzing the measurement properties of patient-reported outcome (PRO) instruments. The collection provides an overview and example application demonstrating how different psychometric methods can be used to develop and refine PRO measures.

Prior to journal submission, the set of papers was approved by the ISOQOL Board of Directors and is available on ISOQOL’s Resource Center in the endorsed papers section.

The first paper in the collection is, “Many ways to skin a cat: psychometric methods options illustrated.” In it, Dr. Donald Patrick introduces the three psychometric approaches analyzed in the following papers, all of which are used in many published articles, and each one has different assumptions, approaches, and statistical techniques behind them. Dr. Patrick also introduces the selected data source for the comparisons – the PROMIS®  Emotional Distress – Depression Item Bank version 1.0.

In the second paper, “Psychometric evaluation of the PROMIS® Depression Item Bank: an illustration of classical test theory methods,” Dr. Sandra Nolte and colleagues describe the first psychometric approach: classical test theory. Overall, the item bank performed well and was reliable when using this methodological approach.

The third paper is “Psychometric performance of the PROMIS® depression item bank: a comparison of the 28- and 51-item versions using Rasch measurement theory.” In it, Dr. Sophie Cleanthous et al. illustrate an example application of Rach Measurement Theory in the evaluation of PRO measures. The study found that overall reliability was good for sets of items, but there was sub-optimal sample measurement.

The final psychometric approach is described in the paper “State of the psychometric methods: patient-reported outcome measure development and refinement using item response theory.” Here, Dr. Angela Stover and her team demonstrate:

  1. Using item response theory (IRT) and how well it works
  2. Determining if different demographic characteristics affect items’ performance
  3. How to choose the best items to use when making shorter questionnaires

Finally, Dr. Jakob Bjørner provides a critique of the three evaluations in “State of the psychometric methods: comments on the ISOQOL SIG psychometric papers.” The paper examines how much the validity and reliability of a PRO tool depends on the psychometric approach used. While there are differences between the three approaches analyzed, there was a large amount of agreement between the results from the methods.

This collection of papers was edited by Dennis Revicki, PhD, who passed away in May 2021. Dr. Revicki was a co-founder of JPRO and served as Co-Editor-in-Chief from 2016 to 2020. A memorial fund was created in his name to commemorate Dr. Revicki for his contribution to ISOQOL. This fund honors his dedication to ISOQOL by awarding JPRO submission waivers to eligible applicants on a quarterly basis.

This newsletter editorial represents the views of the author and does not necessarily reflect the views of ISOQOL. 

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The International Society for Quality of Life Research (ISOQOL) is a global community of researchers, clinicians, health care professionals, industry professionals, consultants, and patient research partners advancing health related quality of life research (HRQL).

Together, we are creating a future in which patient perspective is integral to health research, care and policy.