I played him and was defeated with vigor and alacrity.
I have Elo’s book. It is all about measuring performance over short and long periods of time, not about specific chess knowledge. His historical comparison of great players performance against peers provided a way to set up a rating system as he had benchmarks for the metrics. He did not measure performance against available chess knowledge. There were fewer books and, of course, no computers in that long ago era. Players back then studied games from newspapers and available tournament books. It is not clear whether the great players used or focused their attention on books. As Alekhine once remarked when he was questioned why he did not play a “book” move in a game, “I am book.”
In the early 1970’s, most of the “book” opening theory that US players used was based on Modern Chess Openings (MCO). Players would often memorize lines from the columns in the book. Their endgames were formed by following Reuben Fine’s “Basic Chess Endings.” Class B players would play openings fairly well as well as play endgames okay. The middlegames were less well developed because there were few good books on tactics and strategy, topics that require a lot of time to learn. Stronger players would have to be better at dealing with nuances of move orders and have more skill at tactics to beat the gritty Class B players who learned defense from studying Nimzovich games. In addition, at that time we used different, longer time controls which allowed lower rated players more time to think. Having played a lot of games at that time going from Class B to Expert, players from that era compare okay with players today in most skill sets except for deeper, more complicated tactics.
The book revolution started in the late 1960’s during the time of Fischer’s ascent. Books from Chess Digest on the Grunfeld and King’s Indian defenses were more complicated, have a style more like tree analysis rather than the generalities of earlier books on the opening. Options were explored to greater depth referencing exact games. The Informant series started around 1966, which were quickly followed by ECO which were much deeper than MCO. ECO plus the Informants became the basis for strong players to keep their opening knowledge lead on lower rated players for a time. The Informants had hard tactical and endgame puzzles to do, too. As the 1970’s rolled along, a ton of new opening books and books on tactics came out which were snapped up by the chess public. Endgame book sales lagged, as some European and Russian books on the endgame that were translated to English were difficult to wade through. This book revolution raised the boats of many players, who just by studying, were improving their skills. It was still hard to raise the ratings though, because they were still playing against the same opponents who were learning the same skills. Rating increases came at the expense of the influx of thousands of new players to the game because of Fischer.
The book revolution was enhanced by the computer revolution of the 1980’s and 1990’s. Computer playing programs improved. Databases with games went on the market. The books started to cover more topics in strategy, sacrifices, tactical motifs, candidate moves, move orders, chess psychology, defensive play. These new books superseded Euwe’s books on the middlegame as well as Reuben Fine’s “The Middlegame in Chess” which were the go to books for an earlier generation. Russian books on different topics were translated and filtered into the West. Their detailed analysis and style of thinking began to permeate play in a way that was different, more intricate and subtle than the straightforward and simple methods US players were used to playing based on the play of fellow Americans, like Fischer, Evans, Reshevsky, and others.
The new generation of players of the post-2000 period have the benefit of being steeped in technology as well as having thousands of books, videos, computer programs, databases to use. Sifting through so much information is a skill in itself. Memorizing is still a necessary part of the repertoire of the player, just as it always has been. Players may know a little more, but they still have to perform and may not score any better than their peers from 50 years ago because they have new issues related to faster time controls. I have not found the young players today have the ability to “grind” like similar rated players of the past. Their technique in endgames is not as good. They may have the information available, but still do not study endgames. That is something that only 2000+ rated players find of value. Young players go for the quick tactical kill after playing a memorized opening variation. In faster time controls, there are more mistakes. Alert players jump to exploit these rather than play strategically to carry plans based on pawn structure.
Rating systems do not account for knowledge, time controls, computer use, endgame technique, revolutions in book publishing, or familiarity with technology. These systems do not measure what we think of as “strength” or what we think that a Class B player or an Expert is supposed to know. Everyone has gaps in knowledge and skillsets. These don’t always get exploited in tournament play. All a rating system can measure is tournament performance for a discrete period of time. The ones and zeros are the only things measured. A player can be outbooked but still win with imagination and grim determination. One can still lose by blunders, lapses of attention, and crackups in time pressure. Gains or losses of a few rating points in any single event do not mean much. The numbers do not measure quality of play. Numbers are too narrow for that.
Quiz: how did Elo determine the range of values we use for ratings? What anchor points, if any, did he set, and how were they defined?
Heck, he originally wanted ratings to only be 2 digits! 
That doesn’t change the validity of Prof. Sloan’s question, however. In your answer, you can round to the nearest hundred, if you wish.
Bill Smythe
I was just adding to Prof Sloan’s (implied) list.
Some will enjoy this: web.archive.org/web/201410051358 … arpad-elo/
The German, or Ingo, system was a two digit system where the lower your number was, the stronger you were considered to be. A player aspired to have a rating in the single digits and as close to 1 as possible. The BCF system has three digits. If you have a two digit rating, you are a low rated amateur. A 150 rated player is equivalent to 1800 Elo. A 200 rated player is a master. FIDE’s system was created after the USCF rating. I am not sure how equivalent the USCF and FIDE system were back in the day when they were designed. Canada has a rating system which parallels the FIDE ratings.
Elo says in the book that most of the fledgling rating systems of the time he was working on his rating system and historical comparisons were all four digit systems. He decided to go with that. It appears that the last two digits are placeholders, more of use for TDs to list the players for pairing purposes, rather than having any particular interest for rating. The 200 point intervals were more important for distinguishing “strength” of the players in comparing them.