The ATC Volatility Metrics | RotoGraphs Fantasy Baseball

The 2025 ATC Projections, an aggregation of various projection systems, have been released by FanGraphs. ATC uses historical performance to assign weights to different data sources, similar to Nate Silver’s political forecasting methods. ATC has been consistently ranked as the most accurate baseball projection system by FantasyPros. It introduced three volatility metrics prior to the 2021 season to provide insight into the shape of underlying data. The new volatility statistics – Vol, Skew, and Dim – aim to simplify the quantification of player projection risk. Process risk, inherent due to sample size, and parameter risk, uncertainty of true expectation, are factors that contribute to projection volatility. ATC’s ability to combine multiple sets of expectations helps reduce parameter risk. The system’s volatility metrics provide a way to analyze projection risk based on the distribution of underlying projections. The example of two player projections, Mason Saunders and Charlie Hustle, demonstrates how projections can vary in terms of range and symmetry around the mean. The article discusses how different projection systems produce outlier projections for players like Mason and Charlie, leading to varying levels of statistical skewness. The ATC system generates volatility metrics based on standard deviation and skewness to provide a clearer picture of projection variability. Additionally, the concept of profile risk is introduced, highlighting how one-dimensional players like Daniel Vogelbach can have a significant impact on fantasy team balance if they underperform, compared to five-tool players like Willie Mays. The ATC Dimension metric measures the balance of a player’s category contributions, with larger values indicating a more balanced profile. The ATC Dimension (Dim) is a new metric based on a player’s component categorical Z-Scores with a numeric range from 1 to 5. It is more intuitive than the previous IntraSD and can help determine a player’s multidimensionality. Players like Luis Arraez and Xavier Edwards have Dims around 2.2, making them two-category players, excelling in specific areas. On the other hand, players like Cody Bellinger and Wilyer Abreu with Dims of 4.7 are close to being five-dimensional, contributing well across categories. ATC Volatility metrics can impact rotisserie earnings, showing a negative correlation between earnings and volatility, especially for players with extreme volatility. Skew also plays a role, favoring players with positive Skew, particularly in the mid-rounds of drafts. In terms of ROI, ATC Skew can lead to significant differences in earnings for pitchers. For hitters, ATC Dimension has less impact on earnings, with higher-dimensional players potentially adding more value towards the end of drafts. The future of fantasy baseball lies in understanding risk and volatility, with ATC metrics being just the beginning of a journey towards risk quantification in the sport. the given text so that the main points are preserved while unnecessary details are removed.

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