Between-group vs within-group changes

We know that a most conditions will improve or fluctuate with time, but how much does that effect research outcomes?

To help answer this we are looking at the 2024 paper - Regression to the mean for physical function and quality of life in clinical trials for symptomatic knee osteoarthritis - Martin Englund and Aleksandra Turkiewicz

- What is regression to the mean?

- How can we measure it?

- How does this effect research outcomes?

- What does this mean for us and our patients?