I didn't get the impression only bad data was fixed, instead they used model misfit to highlight deficiencies in the model (it didn't account for all informatio

I didn't get the impression only bad data was fixed, instead they used model misfit to highlight deficiencies in the model (it didn't account for all information, namely the motion of the satellite) and then updated the model. The question becomes at what point does adding more degrees of freedom to your model lead to overfitting, though for reasons I've never felt fully confident in, Gelman tends to assume that Bayesian methods don't overfit.