Cambridge Chronicle Op Ed
Here is the bottom line:
Boston (Suffolk County) with its large black population and relatively low unemployment was immune to Brown's appeal. The I-495 belt was attracted to Brown even in the counties with low unemployment.
However for all counties outside the I-495 belt, there was a strong relation between unemployment and Brown's appeal. Where unemployment was less than 8.5%, Brown only got about 38% of the vote. On the other hand, when unemployment was over 8.5%, Brown's appeal was very high, gaining about 60% of the vote. Eight and a half percent unemployment seems to be a tipping point.