Choose the Best Coach Based on the Theory of Grey System

Abstract

In order to select “the best all time college coach” across both genders and all possible sports, we establish a multi-hierarchy evaluation model based on the theory of grey system. Without affecting the reliability of the results, we analyze the distribution of every index to determine the initial screening standard, narrow target range and simplify the problem. Then, we use the theory of grey system to evaluate coaches. We first normalize all indexes to make them comparable. Second, we determine a set of the best indexes as the reference vector and obtain the correlation coefficient matrix. On the issue of the weight of all indexes, we introduce the concept of dynamic weight matrix by considering the distribution and relative size of them. After that, we obtain the value of the final evaluation from the correlation coefficient matrix and dynamic weight matrix .As for the influence of time on the evaluation, we regroup the data of coaches according to the time section for five years, which results in some statistical variables, and then we draw the trend graph of them. To sum up, the number of excellent coaches of every sport is increasing over time, but the average value and standard deviation of winning percentage is decreasing. The model has the adaptability on different sports by comparison. And because the data of women coaches is insufficient, the influence of genders on the evaluation needs to be researched further.