Why the Senate forecasting models differ  May 6  “There’s not a
data journalism bubble (IMO) but there’s quite possibly a senate
forecasting model bubble,” tweeted Nate Silver yesterday
after Election Lab was launched.  Thus far, I think there are
three formal forecasting models out there: ours, The Upshot’s
(affectionately known as Leo), and that of political scientist
Alan Abramowitz.  In addition, there are Silver’s initial
expectations (not yet formalized in a model, I believe) and the
informed views of handicappers like the Cook Political Report,
the Rothenberg Political Report  and Larry Sabato’s Crystal
Ball.  (The Upshot has a useful chart summarizing the views of
all.)  There is a rough consensus that the GOP is likely to gain
Senate seats, but no necessary consensus on whether they will
gain enough to control a Senate majority.  Our current forecast
gives the Republicans a higher likelihood of taking the Senate
(82 percent) than does The Upshot’s (54 percent).  The Upshot’s
team provided some though