Speed Ratings - Going Correction?

[Fletco]

Hi All A question to anyone compiling their own speed ratings. How do you adjust for the going? I know the correct way, to take each race and compare it to the standard and hence workout the ‘average’ correction required per furlong. Whilst I accept this is the correct way, it is quite long winded, having to look at the times against standard for every race at the meeting each time you want a correction. Does anyone have any ‘rule of thumb’ adjustments for variable goings (F, FG, G, GS, S, H etc.) Any suggestions much appreciated Regards Fletco