Bandwagon effect?
Barack Obama leads John McCain in Gallup Poll Daily
tracking interviewing conducted Wednesday through Friday by
an identical 52% to 42% margin among both
traditional likely voters and
expanded likely voters. Obama leads by a similar 52% to 41%
margin among all registered voters.
This is the first time since Gallup began estimating likely
voters in early October that there is no difference between
Gallup's two likely voter models. Obama's lead of 52% to 42%
using Gallup's traditional estimate of likely voting criteria
takes into account past voting as well as current intentions.
Obama's identical lead using the expanded model takes into
account only current voting intentions.
I'm having a hard time thinking of any particular reason why what
was a
2-point race on Monday should have swung so strongly in
Obama's favor in the span of five days. If this Gallup swing is
real -- if a tsunami of late-deciding voters pushes Obama to a
double-digit win -- the likely explanation will be bandwagon
psychology. The marginal undecided voter wants to vote for the
winner.
