I know you are the HR guru of MN flowery and you were once very helpful to me : so I am, therefore , surprised that you don't understand how teachers think about pay : their own and that of others.
But, to reiterate, even if I were motivated by PRP (and I am clearly not ) there are too many complicating factors in teaching to create any sensible performance measures. What about home tuition as a factor? Classes perform better of a large number of students have supportive -or even pushy- home environments. Nearly every class I teach is shared. So what happens there? And what about inheriting a class from someone else? Whose results are they?
There is a published payscale (which nearly all schools use even academies) and I think teachers have always accepted that we all move on up it to recognise length of service in the profession : when UPS was introduced that gave longer servers a chance to progress beyond the masses and there are now also other opportunities either existing or in the offing outside of normal responsibility based promotion, such as SLEs.
I do think it is all too fraught and subjective.
Out of interest, what public sector jobs do have PRP? Showing my ignorance here , but do doctors? Nurses? social workers? Police? I know that NHS trusts have performance measured and police forces etc but do the individuals?Surely again those would be disincentives to move into complex , troubled or difficult cases.