another startling performance from ted lilly saved the chicago cubs from a sweep in philadelphia, but some considerable damage was done nonetheless. the cubs (including lilly's win) have lost four of six, and in so doing altered significantly the profile of the club as viewed through this page's recently explored metholodogy.
saturday's loss not only put the cubs eight back of the milwaukee brewers, but proved to be a crossover point in terms of run differential. with the trend having turned negative -- in spite of not reaching an upside extreme -- it would seem that run differential data are indicating that the cubs best work may be behind them, at least temporarily. the shorter-term measure of pythagorean record, while still positive, is collapsing; crossover points are normally followed by a move of the 12-game measure into sub-.500 territory. this needn't indicate a disaster for the team -- as the calendar advances, past wins will be falling out of the 12-game sample. it's conceivable (though perhaps unlikely) that the club will play winning baseball even if probability holds and their differential contracts further over the coming week.
it should be noted that the resolution of this downswing may tell us a very great deal indeed about the 2007 cubs. in general, it seems in the study conducted thusfar that downside crossovers for stronger teams tend to be (not unexpectedly, of course) milder events. the 2004 club tended to see its 12-game pythagorean dip into sub-.500 territory usually only for brief spells of a handful of games, during with the macd line would touch a local minima and rebound smartly. moreover, as previously noted, pythagorean record for the year-to-date begins calming down as the sample size approaches 60 games, often giving a significantly better indication of how the team will fare over the remainder of the year than we can have now. at 35 games, the figure is .579 and trending down; where it trends down to in early june may be revealing.
one might also note the indications of the milwaukee brewers.
in spite of hope for a correction following game 33, the brewers' trend instead fought its way to a much higher maxima in their saturday win in new york. from a 12-game pythagorean reaching .866, a correction is nearly inevitable -- such runs of success are simply unsustainable. like the cubs, the games falling out of the back of the 12-game average are wins, some considerable -- again, this doesn't necessarily presage a total collapse, and the signal is perhaps not as pessimistic as the crossover which has befallen the cubs. but a moderation of their pace is nonetheless to be expected.