A good example of this spin can be found at Labour List, who are trying to suggest that Ed Miliband is actually scoring higher in the leader approval ratings than any of a series of four Conservative party leaders, also in opposition at the time, at a similar stage in their leaderships (i.e. 3 months in).
Unfortunately the figures they quote tell a different story, on the whole. Here's the relevant chunk from LabourList (placed on the public record here, just in case they decide to amend it later):
"The comparative MORI polls from previous opposition leaders puts him in much better light. Hague was 22-28 satisfied-dissatisfied after three months; IDS 24-22; Howard 30-22; Cameron 32-19 while Miliband was at 35-34."Yes, that puts Hague at minus six; but Iain Duncan Smith works out at plus two, Michael Howard at plus eight (not bad!), and David Cameron at plus thirteen (impressive!) no less. Thus only Hague had a lower score than Red in this direct comparison. Are the contributors to Labour List innumerate, or what?
Meanwhile, Ed Mili is in reality sinking; but if Labour are unwilling to face up to that fact, well, so much the better for the political right!