Originally Posted by WAKEUP
It's called 'post hoc ergo propter hoc'
Your evidence isn't evidence at all.
If you are going to get Logic 101 on us, I propose that you are really looking for cum hoc ergo propter hoc. Correlation does not equal causation.
A and B cause C which causes D (string of causation)
Steroid use at an age older than 25 is associated with increase of hitting power outside of a typical growth curve.
Therefore increase of hitting power outside of a typical growth curve is caused by steroid use.
In this example, the correlation between steroid use and increased hitting power/age does not imply that steroid use causes the increase of hitting power at an advanced age. Although some folks might be suspicious of players that experience an increase in hitting power at an age outside of the typical growth curve... but that does not make the conclusion valid.
Zach Rymer of the illustrious Bleacher Report typed up a nice piece on how Yadi improved. Largely it was in how and what he was hitting not in his actual power. Bottom line... he is hitting fastballs better than he ever has in his career and putting more of them to his pull side. A Righty that can line drive into the left field leaves a lot of room for improvement for extra base hits without an overall increase in hitting power, especially if they are against fastballs. If his first 6 years were lots of line drives/hits to his power side, and right into defenders, or close to defenders.. that can explain the lack of extra base hits.
In my mind, what should draw suspicion is if his 2005 hitting style matched his 2012 style.... just with a lot of extra pop. A little Fan Graphs research will show you that's just not the case.
Here is some interesting reading: