How to analyze and present work productivity loss due to health problems in clinical trials?

Project Summary

Health problems can have an adverse impact on work productivity of patents and their caregivers. Patients and caregivers might have to stop working, reduce their routine work hours, miss work days, or may not be able to perform their work at their full capacity.

Work productivity loss has been considered as an important outcome for clinical trials to measure. However, the analysis of work productivity loss data often requires complicated statistical methods due to the nature of the data—namely, that the data usually contains a relatively high proportion of people who have zero losses and a high proportion of people who stop working, i.e., lose all work time.

Our two objectives were:

  1. To compare the statistical performance of different work productivity loss analysis methods.
  2. To develop and assess different ways of communicating analysis results to non-technical users (e.g., patients and caregivers)

Project Findings

Objective one: Comparing statistical methods

We found there is a lack of consensus on how to measure, analyze, and present work productivity loss outcomes in recent clinical trials. We found that work productivity loss in recent clinical trials is often partially measured and commonly analyzed using assumptions that may not be met. Our study suggests that selecting an appropriate statistical method to analyze work productivity loss depends on the sample size and the data distribution of work productivity loss outcomes in each treatment arm of a clinical trial.

The diversity of measurement and analysis methods used in literature may make comparability challenging. There is a need for guidelines providing recommendations to standardize the methods used to measure, analyze, and report work productivity loss outcomes in each treatment arm of a clinical trial.


Objective two: Ways of communicating work productivity loss results to patients and caregivers

We found, in our interviews, that patients and caregivers want to be provided with:

  • Lay terms about what each work productivity loss outcome mean
  • Visual support for each productivity loss result
  • Calculation examples when cost results are presented


From our survey, we found that:

  • Patients and caregivers identify the same work productivity loss outcomes as “important to report”
  • Patients and caregivers think it is important to report all outcomes in days and in cost


Zhang, W., Sun, H. How to analyze work productivity loss due to health problems in randomized controlled trials? A simulation study. BMC Med Res Methodol 21, 130 (2021). (Objective 1)


Dr. Wei Zhang and Jacynthe L’Heureux presented preliminary findings in December 2021 in the Work in Progress Seminar Series held at the Centre for Health Evaluation and Outcome Sciences. (Objective 2)

We are also expecting to present at the upcoming 2022 BC Support Unit Conference: Putting Patients First, in March 2022. (Objective 2)


This project is part of the Real-World Clinical Trials Cluster.


Wei Zhang, PI ✉︎
Huiying Sun
Paige Tocher
Julie Sou
Lin Chen
Jacynthe L’Heureux ✉︎
Gary Johns
Theodore Steiner
Helen McTaggart-Cowan
Yike Huang