It's supposed to be subjective; they aren't measuring pain against some objective measure or even against other patients, just how you're feeling personally. T

It's supposed to be subjective; they aren't measuring pain against some objective measure or even against other patients, just how you're feeling personally. This number will be used to determine if a more in depth tool is needed (like if you say 7-10). What type of treatment is needed (pain tolerance is different from person to person, so even if two people have the same injury or disease, one might say 8 and need pain killers and the other might say 3 and not). It will be used to gauge if a treatment is working (when you first came in you were at a baseline of 6, but after taking this treatment, you're at a 2), and so on. Thus, a personal scale makes sense.