The midfield of a team decides the ball possession within a match. The higher the ball possession, the bigger the chance of receiving more regular chances.
Midfield is primarily derived from:
LLoko (Lokomotiv Lund, ABC of tactics) has made an investigation on the ball possession to number of chance ratio which shows that the number of chances is not linear to the ball possession; from 65% and upwards, it is very likely that the opponent will not receive a single chance. This knowledge is the basis behind the so-called "All out tactics".