The evaluation of the motor behavior in collective sports games: presentation of a scientific tool applied to physical education The present research is an attempt at putting to cross-checked test, the delicate evaluation of motor behaviour, in the field of collective sport game playing in physical and sport education. Our purpose is to build up a tool of calculation, which can estimate, in an homogeneous and relevant way, the ease of the movement of the actors during those activities. In that prospect, our choice has turned to motor behaviour that have several characteristics in common ; namely operative motor interaction with others (presence of partners and opponents), a mediative object (ball), and a standardised achievement space (a gymnasium). Thus we evaluate the pupils in three traditional games (ball to the captain, ten player passe, rounders). Evaluation is carried on observing recorded video-tape and building up observation grids. The latter being filled-in by ourselves, taking into account the number and quality of motor interaction produced by the actors. Finally, the validity of the tool and the objectiveness of the experimenter are tested by means of the \u201cmethod of the judges\u201d, in which the point is to compare the marks given by the researcher, to those given by the judges specialised in collective sports games.<\/p>\n