Are people with chronic pain more diverse than we think? An … : PAIN
here are commonly investigated in chronic pain: pain intensity, pain interference, depressive symptoms, psychological flexibility, and pain catastrophizing. Data were collected twice daily for 42 days from each participant and analyzed in 2 ways: as separate cross-sectional group studies using the timepoints as the separate data sets (between-person) and as individual longitudinal studies using each person’s time series data (within person). To confirm ergodicity, the results from the 2 analyses should agree. However, this is not what was observed in several respects. The between-person data showed substantially less variability compared with within-person data. This was evident in both the summary statistics involving single variables and in the correlational analyses. Overall, between-person correlations were relatively restricted in range, while within-person correlations varied widely. These findings have potentially profound implications for the field of chronic pain research. Bec
