Thanks for the question. There are 3 reporting agencies, Transunion, Equifax and Experian.
Each uses 175 criteria to grade or assess you. Experian is by far the most USED agency when credit is obtained, but it is also the most stringent with scoring which pleases lenders of all credit categories.
With mortgages, lenders use ALL 3, then they throw out the highest and lowest and accept the middle score as the final score.
I hope this is useful, please contact me direct with any further questions.