The funny thing is that I am certain that over 50 years, I have witnessed more elite base stealing threats on first base than is covered under that statiscal "study" that is based on data from 2003-2005. Easily 10 fold more. Is it evidence what I saw? Of course it is. Is it conclusive evidence? Of course not, and neither are these so-called studies. The effect a baserunner has on a pitcher a batter differ enormously depending on the individuals. Many batters are completely oblivious to the runners on base. Others seem to be engaged with and part of the baserunning strategy. Other batters, it bothers. I don't think a runner on first base bothered Yaz, because he often spoke about making a living using the hole in that situation. I do know that he hated players dancing on second base. He would tell them to stand still and he would drive them in. I suspect that these stories annoy you because you think I am presenting them as some sort of anectodal evidence. I am not. These stories are part of the beauty and fabric of the game to me, and this is a forum where I can tell them.
As far as this issue of proving statistically whether a speedy runner on first base has a positive or negative impact on a batter's performance, the real answer is sometimes it does and sometimes it doesn't. It depends on the individual's involved. The data has no predictive value at all. It would be like using a study that that says 60 percent of people prefer chocolate ice cream to conclude that chocolate ice cream is superior. I realize that this is a bad analaogy, because chocolate ice cream is superior. LOL! Anyway, Kimmi, we can both agree that these surveys are not perfect, and some are less perfect than others. I like the statiscal aspect of the game, and I don't discount it at all. I am not the traditionalist that you think I am. My father taught me about the statiscal folly of the bunt and the insufficiency of relying on batting average befoe Bill James hit puberty. I also have realized that some times those assumptions and statistics get thrown out the window. If you have a guy who can get 20-30 bunt base hits in a season and his success rate is very high, it is a weapon. For most players, bunting is just to be used as an element of surprise and it is otherwise a wasted AB. I like to look at statistical studies, but I also recognize shoddy work for what it is.