Whiff + (Heat+ update)
About a month ago, I released my first writeup on my initial stuff model Heat+. Since then, in between class and spring break, I've made some major upgrades and fundamental changes to the model that have greatly improved whiff rate prediction power. I've also renamed the model, from Heat+ to Whiff+ because I think that sounds better and is more descriptive of what the model tracks. In terms of future changes, I would like to implement a location aspect to my model, as fastballs at the top of the zone are much more effective. Fundamental Change The biggest change made comes from what outcome the model is being trained to look for. Stuff+, Heat+ and PitchingBot are trained on Run Value, meaning it looks at the true outcome of the pitch. Whiff+ is trained Whiff Probability, meaning it looks at whether or not the batter made contact with the pitch. This removes a lot of external factors and focuses more on the physical qualities of the pitch and its a...