This is a list of films voted the best in a notable survey--either by critics or by the public. Some surveys focus on all films, while others focus on a particular genre or country. Both national surveys and worldwide surveys are included.
The winner of a survey may depend on the voting system, which differs from poll to poll. Some surveys suffer from biases such as self-selection or skewed demographics, or may be susceptible to vote-stacking.
Every decade, starting in 1952, the British film magazine Sight & Sound asks an international group of film critics to vote for the greatest film of all time. Starting in 1992, they invited directors as well, to vote in a separate poll. 63 critics participated in 1952, 70 critics in 1962, 89 critics in 1972, 122 critics in 1982, 132 critics and 101 directors in 1992, 145 critics and 108 directors in 2002, and 846 critics and 358 directors in 2012.
This poll is regarded as one of the most important "greatest ever film" lists. American critic Roger Ebert described it as "by far the most respected of the countless polls of great movies--the only one most serious movie people take seriously."