To state up front, I have been a rabid Astros fan who has worn my "Dickie Thon" jersey everyone from Wrigley Field in the 1980s to Yankee Stadium for Game 5 of the 2019 playoffs. However, I tried to make this an unbias reading based on OPS (not the perfect stat, but a good stat that even casual fans understand quickly as slugging average plus on base percentage).
The quick history recap; pitchers work hard to trick batters starting with throwing fast pitches inside and softer pitches outside to throw off their time. Opposing baseball players have always tried to steal the sign from the catcher to tip off their teammate at bat on which pitch is being thrown (fast ball vs. off speed pitch) and location. Using electronic equipment started at least as early as 1951 when the famous "shot heard round the world" was partly made possible by the sign being stolen from a camera in the outfield. This practice was not actually banned until a decade later by MLB.
To layout the case for Astros haters; 1) MLB caught on in 2017 that they Astros were using cameras of some kind to steal signals and sent out a memo to all teams to make it clear electronic sign stealing was NOT allowed. 2) MLB concluded, and the Astros later admitted they were stealing signs from cameras and using methods such as banging on a trash can to signal batters. 3) Critics charge and the Astros deny that buzzer's were used to signal players, in particular charging that Jose Altuve's series clinching homer of a high and outside Chapman fastball was tipped off and noting Altuve told teammates not to tear off his shirt which they conclude was meant to prevent the buzzer from being discovered. 4) The Astros contend halfway through 2018 the players decided to stop the practice because it becoming a distraction, though they seemed to continue to be good at picking up on pitches in at least one playoff case in which a Tampa pitchers was lowering his glove for on pitch and leaving it high for another - though this kind of tipping is not considered against the the rules. In the World Series game against Washington, Strasburg's coaches realized he was tipping the pitch by the way he held has hand in the first inning when the Astros were teeing off on his pitches, and found that by shaking his glove every pitch they could no longer steal the pitch and he was almost unhittable the rest of the way.
Let's look at what the numbers say:
|2017 OPS||2018 OPS||2019 OPS||3-year average|
|Astros batting home OPS||0.812||0.730||0.878||0.807|
|Astros batting road OPS||0.834||0.777||0.819||0.810|
|Home better hitting at home than road||-0.022||-0.047||0.059||-0.003|
|Opposing batting OPS playing in Houston||0.688||0.647||0.683||0.673|
|Opposing batting OPS in Astros away games||0.753||0.632||0.678||0.688|
|Opposing hitting better at home than road||-0.065||0.015||0.005||-0.015|
|Estimated extra advantage for Astros hitters||0.043||-0.062||0.054||0.012|
In 2017, when the Astros admit to cheating, their OPS was actually 0.022 points lower at home (where cameras could steal signs) then on the road (where cameras were presumably not available). At first glance, another Astros fan might arguing the cheating was not working during the season. However, Minute Made Park was playing as a pitchers park overall, and opposing batters actually hit 0.065 points worse in Minute Made then when the Astros came to their park. Therefore, my estimate it that the electronic sign stealing did help the Astros improve their OPS by about 0.043. In my Statis-Pro game that is about 1 home run number, so if I'd discover this then I would suggest taking the top home run number from every 2017 Astros card and change it to a strikeout to undo the advantage they gained.
However, taking 2018 and 2019 combined the Astros did not appear to have any advantage at home verses on the road, which would seem to back the claim that those two years stats are honest. The overall average is that their home batting was slightly better than road batting, but actually visiting teams improved just slightly more in Houston (0.004 between the two years, with road teams having a 0.062 better OPS advantage in Houston in 2018 and Houston having a 0.054 better OPS in 2019.
A skeptic could conclude they found new ways to cheat in 2019 since that year was better even than 2018, but for my purposes of whether or not the zips projections are off - the Houston home big "disadvantage" in 2018 makes the overall OPS over the past three years that go into Zips ratings only show a very slight advantage for Houston.
For my game, I decided to have one extra number on all Houston batters turn into a DEEP drive that might or might not go out rather than an certain home run.
Therefore, when a 2019 Houston pitcher card is on the mound in a game I will just chance the top home run number and first strikeout number on the opposing batters card and change it to a DEEP drive as I do with all others.
However, if a 2019 Houston batters card is in play, I will change the top TWO Home Run numbers and only the first strike out number and change them to DEEP drives. On average, that would make the OPS of Astros batters end up about 0.027 points lower than their normal card.