Gate and wind factors were introduced by the 2009 rules, to allow fairer comparison of results for a scoring compensation for variable outdoor conditions. Aerodynamics and take-off speed are important variables that affect the jump length, and if weather conditions change during a competition, the conditions will not be the same for all competitors. Gate factor is an adjustment made when the inrun (or start gate) length is adjusted from the initial position in order to provide optimal take-off speed. Since higher gates result in higher take-off speeds, and therefore present an advantage to competitors, points are subtracted when the starting gate is moved up, and added when the gate is lowered. An advanced calculation also determines compensation points for the actual unequal wind conditions at the time of the jump. These points are added or withdrawn from the original scores of the individual jump according to the wind conditions; when there is back wind, the points are added, and when there is front wind, the points are subtracted. Wind speed and direction are measured at five different points based on average value, which is determined before every competition.