Looking at the numbers with all teams but 2 there is a better record at home than away. At least one exception I think proves the rule, Phillies are .500 at home and .632 away (that just goes to prove nobody likes playing in Philly not even the Phillies.)
The biggest differentials between Home and Away percentages are:
Detroit with a .263 difference, San Fran .248, TB .235, Bos .214, Pit, .206, Cubs .203 (just because they are used to peeing in big troughs).
Phillies are -.127 difference and AZ is -.050 as the exceptions.
My question is why?
The obvious and simple answer is an intangible 'being pumped up for the home crowd'. But, that definitely doesn't explain Phillies relative troubles at home. Is it a park thing, the team is built to that specific park's quirks. Like having a team that tends to pop high into left, which = HR over Boston's Green Monster but not in other parks.
Why is is also that the ALE teams all have a percentage difference over .118 where no other division has more than 2 teams over that same percentage difference in favor of home. Are ALE teams just lazy on the road?
Anyways, I do not have the math or time to really adequately answer these questions but I would like to hear at least some theories.
It does seem the Angels and Marlins would be the most professional if it is a simple explanation of being pumped up for the home crowd..professionals should be equally pumped for every game Angels are a mere .015 game diff.