In the National Football League (NFL), a tied game occurs when a regular season game ends with both teams having an equal score after one 10-minute overtime period. Ties have counted as a half-win and half-loss in league standings since 1972; before that, ties were not counted in the standings at all. Tie games were once frequent in the NFL, but have become uncommon due to a rule change in 1974 that extended the existing sudden-death overtime for postseason games into the regular season. As a result, ties are most often the result of mishaps or mistakes from the teams involved. Tied games are considered to be the least desired outcome a football game can produce.