The ATC Projection System by Ariel Cohen March 1, 2017 We are pleased to announce a new projection system, “ATC”, is available on FanGraphs. It can be found on the projection pages and is also available in the auction calculator. Today we are introducing to the public, the Average Total Cost Projection System (ATC Projection System). The system gets its name from the fact that it “averages” many projection systems together. The ATC system does not simply take a straight average of all the projection systems. Instead, each system accounts for a different weight for each statistic for which it projects (The weights are based on historical past performance). For example, System A might be given a 20% weight for batter homeruns. but just a 5% weight for pitcher strikeouts. System B might have a 10% weight for HRs, but just a 2% weight for Ks. And so on. The ATC system incorporates ZiPS, Steamer, FanGraphs FANS and other freely available projections, plus prior MLB statistics over the past 3 seasons. There are, of course, some manual edits made along the way, mostly for playing time projections, as we get closer to Opening Day. A good way to understand what the ATC Projection System does – is to picture what Nate Silver does with his presidential election forecasting at www.fivethirtyeight.com. Nate collects polls data, adjusts them, grades them, weights them intelligently, combines them, and then calibrates them. If one polling firm has been more predictive than others in the past – it will receive a larger weight of the aggregation. Nate then adds in some manual tweaks and changes, and he has created a great model which is far more predictive of any one model by itself. Nate Silver does little or no polling of his own … yet his predictive model is the best in the industry. ATC operates in a similar manner, but for baseball. The Average Total Cost System was developed by Ariel Cohen before the 2011 MLB season for the purposes of winning fantasy baseball leagues. Ariel and his fantasy partner, Reuven Guy, have used the ATC system projections in their home leagues ever since, winning half a dozen league titles. In 2015, they finished 2nd in the national Doubt Wars Mixed Auction league, and in 2016 they finished in 1st place in their NFBC New York Auction League. Ariel Cohen is a fellow of the Casualty Actuarial Society (CAS) and the Society of Actuaries (SOA). He is a Vice President of Risk Management for a large international insurance and reinsurance company.