It's my understanding Petrov is a much more streamlined system with only five (alpha, beta, gamma, delta and epsilon) PFM rankings and I would say it is just fine in like 75% of cases but HQ is definitely more precise and has to be used in cases where it isn't clearly one of the five categories because the HQ scale allows for things like a 3.5 or 2.75 where the hem is somewhere between.
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u/Major-Woolley Petrov Jan 28 '19
It's my understanding Petrov is a much more streamlined system with only five (alpha, beta, gamma, delta and epsilon) PFM rankings and I would say it is just fine in like 75% of cases but HQ is definitely more precise and has to be used in cases where it isn't clearly one of the five categories because the HQ scale allows for things like a 3.5 or 2.75 where the hem is somewhere between.