The first modern rating system was used by the Correspondence Chess League of America in 1939. Soviet player Andrey Khachatoruv proposed a similar system in 1946. The first one that made an impact on international chess was the Ingo system in 1948. The USCF (United States Chess Federation) adopted the Harkness system in 1950. Shortly after, the British Chess Federation started using a system devised by Sir Richard Clarke, a statistician and senior civil servant. The USCF switched to the Elo rating system in 1960, which was adopted by FIDE in 1970.<ref name="H/W">Hooper, David & Whyld, Kenneth 1992. "The Oxford Companion to Chess". 2nd ed, Oxford University Press. p332 </ref>