Inter-rater reliability in performance status assessment among healthcare professionals: an updated systematic review and meta-analysis.

The meta-analysis's Pearson correlation coefficient ranged from 0.705 to 0.787; there is notable correlation of performance status scores, with no one tool statistically superior to others. KPS is, however, descriptively better and favored in head-to-head trials. Future studies could now examine the accuracy of KPS assessment in prognostication and focus on model-building around KPS.