We can debate park factors until the cows come home, but now thanks to HitTracker we have solid empirical evidence that we were right when we predicted back in January that Citi Field would be a homerun graveyard. Thirty-six balls have been hit short of the outfield wall in Citi Field this season that would have likely been homeruns at Shea Stadium. Only two -- both poked by Chase Utley into Utley's Corner -- have cleared the fences at Citi that wouldn't have done so at Shea.
Let's be clear about the premise here: the data don't suggest that runs go to die at Citi Field, but rather that would-be homeruns have been turned into something else, most often doubles. Here is the actual result distribution of those 36 batted balls:
Interestingly, all eight flyouts were hit by Mets' opponents. I'll assume this is nothing more than propitious happenstance as far as the Mets are concerned. While the sixteen batted balls on the Mets' ledger all went for hits, neither singles, doubles nor tripes are quite homeruns, and the affect on slugging percentage and, in turn, runs scored, is very real. For kicks, I added the additional bases that have been "stolen" from the Mets by their home park just to see what the results would be.