Is accuracy inverted or something?

Einzelganger7: In world of warships there is a stat named Sigma and according to the wargaming wiki it is described as "Sigma is one of the parameters for gunnery in World of Warships. It describes the tendency of a shell to land closer towards the center of aim, aka the middle of the dispersion ellipse described by 'vertical dispersion' and 'horizontal dispersion'. The higher the Sigma value, the more likely the shells are to land closer to the center." I bet world of tanks has the same parameters but how they work is completely hidden, still I think they linked sigma with dispersion but in this case the smaller the dispersion is also lower the sigma because is ridiculous that derpy tanks almost all the time land their shots pin point.