In this paper a criteria of comparison of different tournament organization systems in sporting contests is offered; the criteria uses the probability of winning the fairly strongest player. Two probabilistic models have been analyzed. Calculating formulas for estimating the probability and probability density of score points gained by one or another player were obtained. Some really used tournament systems were analyzed with the stochastic modeling method. The available results also provide an order of objects presenting to experts while organizing the examination by paired comparison. An analytical estimation of probability of tournament results (or pared comparison) was obtained. In many cases it allows to avoid a time-consuming procedure of sorting out possible variants.