# Understanding the Rprfm

OK i posted an article not long ago on international rating systems created by professor Elo... Well this blog i hope to simplify it even more for u. To measure your Rating Perfermance or (Rprfm) i will give a tournament result that i had back in 2001 for the demo on how its done in case u havnt learned yet. Now i will start by given quick back ground it was a 2 day, 6 round tournament i had an Australian Chess Federation ( A.C.F.) rating of 1580  ok and i scored 4/6 games in this event and my average rated (Rav) player was 1602 so now u got the stats so lets begin to find out how well i played in this tournament.....

Step 1:- first thing i do is add up all the players ratings and then divide that number by how many games i played eg; 6 games in this case. to see what my (rav) is, which means rating average of the players i was playing. so we know its 1602 now how many points diff is it from mine thats the next thing to know,  answer 22 points difference higher then mine, simple enough so far. Now if we look at the table from the article i posted u would see i would expect to have a 47% chance of winning,which is 2.82 /6 close to 3 at most.

Step 2:- Calculate what your actual score and percentage was: to do this u just divide results number from the number of rounds u played  eg 4 divided into 6 . The answer is 66% your calculater would have it as 0.66666666 u leave out the o and all but 2 of the digets... now u will find out y we needed to know the Rav first.

Step 3:- Now we go back to the table as before this time we find out what the player 66% over the 34% one adds up to in points. In this case it between 114-121 so how do we know which way to go well because of the 0.666 factor it be somewhere in the middle so about 117 maybe...

Step 4:- Now to find out what the rating equals all u do is add 117 to the 1602 rating and u have 1719 Rprfm roughly.

Now if i had played worse then expected then u would take away from the 1602 to whatever the table gives for what my actual result was eg is played 1.5 /6 that would give me a rating of 1602-189 = 1413 im sure thats right.If not feel free to say otherwise im sure i worked it out right though.....