Where can I find a description of the "old" USCF rating system (that was in use through the 1990's)? Where can I find a description of the &quot;old&quot; USCF rating system - not the Harkness system, but the one after that, that was in use up until about 2001 when the &quot;new rating system&quot; was adopted?  I was sure I had a copy of this at one point, but I can no longer locate it.  The US Chess Federation Official Rules of Chess, 3rd Edition, has a high-level overview of the old system, but not all of the specifics.
I am particularly interested in a refresher on how the computation of provisional ratings was done.  Based on my recollection, I think that for a player's first 20 games, their provisional rating was the average of their performance ratings for every game they played, calculated as &quot;opponent's rating +400&quot; for a win, &quot;opponent's rating -400&quot; for a loss, simply &quot;opponent's rating&quot; for a draw.  Then after 20 games, a more Elo-like formula was used, with a fixed K factor of 24 for players rated under 2000, or 18 for players rated 2000 or over.  But, I can't find the actual specifications of this anywhere.  The 3rd Edition rulebook does talk about calculation of provisional ratings in the way I described, but it's not clear to me from reading the high-level description if the &quot;average of performance ratings&quot; based provisional rating was carried through the entire 20 game provisional period, or if it was done for a smaller number of games and then something else was done for the rest of the provisional period.
In any case, I'm sure that finding a copy of the actual description of the rating system (which the 3rd Edition rulebook says can be had &quot;free for the asking from the USCF&quot; - though I am not sure they'd still have any copies available of the specifications for a rating system that hasn't been used in about 20 years.  ;-) ) would answer all of my questions - but I just can't locate it anywhere....
I found this page from Glickman which contains the old provisional formula. That formula is:

R[post] = (N R[pre] + mR[avg] + (W - L)400) / (N+m)
where R[pre] is the player's pre-tournament rating, N is the number of games upon which R[pre] is based, m is the number of games the player completes in the tournament, R[avg] is the average of the opponents' ratings, W is the number of wins, and L is the number of losses. If the player is unrated, set N=0 and R[pre]=0. The final result is rounded to an integer.

The August 1994 report of the USCF Ratings Committee discusses the old provisional system a little. There are some details in there, like how unrated players were initially treated as if they had a rating of 1000 when calculating the ratings of other unrated players.