Pair skating, which has never included a compulsory phase like the other figure skating disciplines, did not require a short program until the early 1960s, when the ISU "instituted a short program of required moves" as the first part of pair competitions. Hines reported that the change was due "to a few controversial decisions in the 1950s and the discipline's increasing technical complexities". In 1964, at the European Championships in Grenoble, France and the 1964 World Championships in Dortmund, West Germany, and during the Olympics in 1968, a two-and-a-half minute long technical program was added, later called the short program, which constituted one-third of a team's scores. The arrangement of the specific moves, also unlike compulsory figures for single skaters and the compulsory dance for ice dancers, were up to each pair team. The short programs introduced in single men and women competitions in 1973 were modeled after the pair skating short program, and the structure of competitions in both single and pair competitions have been identical since the elimination of compulsory figures in 1990.