Arnold Kling summarizes how the left-leaning economists can correct themselves,
Look for structural reasons for policy failure, rather than attribute it always to misguided ideology. Consider the implications of imperfect knowledge on the part of government actors. Also, consider that the existence and growth of special interests is at least partly endogenous with respect to policy.
And what the right-leaning economists could do to balance their positions
Look for structural explanations for the growth of the state, rather than attribute it always to misguided ideology. Consider the implications of urban density. Consider that as the economy becomes more complex, the potential dispersion in wealth due to differences in ability, information, and luck becomes very large, while the ability to overcome such differences with sheer effort probably declines.
It may be a good idea to have checklist templates that can enable ideologues and economists from right and left to balance their positions. That is, if they want to do so. In any case, nothing prevents a third party listening to advocacies by such ideolgoues to filter it through the lens of such checklists. How about an "ideology calibrator"?
Update 1 (12/3/2011)
David Leonhardt has this series of links to blindspots of liberals and conservatives on economic issues.