In essence, the proposals built on the work done by Professor Elo in devising his Elo rating system. The establishment of an updated list of players and their Elo rating enabled significantly strong international chess tournaments to be allocated a "Category", based on the average rating of the contestants. For instance, it was decided that 'Category 1' status would apply to tournaments with an average Elo rating of participants falling within the range 2251–2275; similarly Category 2 would apply to the range 2276–2300 etc.