Local council by-elections: the recovery continues, again

Two months on, it’s time to update my post about the trends in local government by-elections.

Week by week local by-election results can fluctuate greatly as the luck of the draw over which seats are up adds to the variations in local circumstances to produce a large spread of results. However, aggregated over longer periods the pattern of local by-elections does say something about the state of the parties, which is why I’ve been looking at the trend in Liberal Democrat performances since May 2011.

This following graphs show the change in the Liberal Democrat vote share in by-elections, measured since the seat was previously contested and – to even out for those local factors – taken in two month averages.