In my post about the new CDF signal of a mysterious new resonance decaying to jet pairs, there is an active comments thread. I posted there a graph crafted by Tommaso Tabarelli de Fatis, a CMS collaborator, who picked the CDF data and simulation and scaled the energy scale of the latter up by a few percent, showing that the agreement of simulation and data was better, and that the bump at 145 GeV could be explained away this way. Below you can see the result of scaling the jet energy scale up by 4% (the jet energy scale is bumped up by just scaling the dijet mass; this is in principle approximate, but it is a good one at that).
I mention this because Tommaso has now produced an animated GIF of the tweaking up of the MC/data Jet energy scale in the CDF analysis, showing how the residues of data minus simulation behave for JES shifts of 0% to 7%. To put this in perspective, you should know that in 2006 CDF published (actually a few physicists from CDF, a dozen of them to be exact, and among them yours truly) an analysis of their Jet energy scale, assessing at 3% the uncertainty on that quantity.
One should also remember that CDF can now verify the agreement of their jet energy scale with simulations to a much better precision than 3%, by fitting the W->jj decay signal in top pair decays when they fit the top quark mass. The current measurements have a precision of 1% on the jet energy scale, in fact. However, one should also consider that the background in the new CDF analysis may be due to gluon-originated jets, which might be subjected to a different jet energy scale with respect to quark-jets that originate in hadronic W boson decays measured in top mass measurements.
In any case, I suggest you to give a look at Tommaso's animated GIF.