This review pulls many studies to showcase the difficulty of predicting pain. There are many factors influencing the pain experience. Pain predictions also change with knowledge of results. Some patients will overpredict pain prior to a task initially, especially if they are fearful of the task, and once they realize they overpredicted, they underpredict subsequent ratings. Greater variability is seen in patients with high anxiety compared to low anxiety. Patients with high anxiety overpredicted pain after multiple treatments but the accuracy improved.
Other studies show increases in future pain prediction when underpredicting an initial unknown response (healthy subjects given electric shocks). The spontaneous mismatch and underprediction lead to increased fear of future shocks and subsequent over predictions. The simple act of asking a patient their pain rating can influence the outcomes of an intervention.