Research Overview


We are conducting research on the evaluation of sports players. In this research, we are dealing with the following two themes:

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What is Player Impact Metrics?


Definition

Player Impact Metrics is defined as follows:

A performance evaluation index that measures the degree of contribution to the Plus-Minus.

We believe that this element is the most important for essential player evaluation. Below, we explain the reasons for this in order.

Structure and Principles of Competition

Almost all ball games have universal principles and principles that come from the structure of the competition.

The principle is that:

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Value of Players and Evaluation Criteria

From the "Structure and Principles of Competition," the value of a player is the degree of contribution to the team's winning, which means the degree of contribution to Plus-Minus.

So what are the "stats" that we usually see?

In short, we believe that they are aggregates of plays (the lowest level of the structure of competition).

For example, the following applies:

However, these are just aggregates of plays to "score points" or "prevent points" and do not reflect the degree of contribution to Plus-Minus.

Moreover, there are many plays that affect Plus-Minus that are not aggregated but exist.

For example, the following applies:

Although these do not remain in conventional stats, it is certain that there is an impact on Plus-Minus, i.e. winning.

In other words, conventional stats have the following biases:

Based on the limitations of conventional stats, we are developing an index to evaluate the degree of contribution to pure Plus-Minus that a player has produced by being on the court/field, i.e. Impact of players.

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<aside> πŸ’¬ There are many talented players who have made significant contributions to the team but are ordinary in conventional stats (play aggregates), such as Shane Battier of the NBA and Andrew Henry Robertson of the Premier League. They are examples of talents that were underestimated and discovered by excellent data analysts such as Daryl Morey and Liverpool's research department.

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Output Image

The specific output image of Player Impact Metrics is as follows.

The interpretation of the figure is as follows:

This enables visualization of the relative contribution of players in the league.

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<aside> πŸ’¬ The degree of contribution can be calculated at any granularity/time axis. It can be calculated for long-term evaluations of 3-5 years, medium-term evaluations of one year, or evaluations at the level of several months or games.

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What is Player Interaction Metrics?


Definition