In episode 14 of season 1 of Inside the Science we’re highlighting the study, Inter-rater reliability of a modified version of Delitto et al.’s classification-based system for low back pain: a pilot study and discussing it with one of its authors Hans van Helvoirt. He shares a look at this paper looking at the reliability of a popular classification system within physical therapy. He explains the appropriate interpretation of this data, how he allows these findings to influence his clinical thinking, the big takeaways, and recommended other work which would shed further light on this topic.