Fortunately we can fact-check that claim. A Hamilton College study examined the prediction accuracy of 26 national columnists - they scored 472 predictions made by 26 columnists and found that:
"The findings, presented in a paper titled "Are Talking Heads Blowing Hot Air? An Analysis of the Accuracy of Forecasts in the Political Media," showed that in general liberal columnists performed better than their conservative counterparts."
"
Paul Krugman, [...]
scored the best."
"Lindsey Graham, Carl Levin, and syndicated columnist Cal Thomas made the most mistakes."
STUDY: Paul Krugman, Liberal Columnists Make Better Predictions Than Conservative Ones
You might not agree with his political views, but the economic predictions of Nobel Prize in Economic Sciences winner Professor Dr. Dr. Paul Krugman are top-notch. (He is by no means infallible - he wrote an article about past mistaken predictions of him and what he learned from those mistakes.)
Some of Paul Krugman's latest predictions, for example the ones regarding the effects of the Republican tax cuts on the deficit were very accurate as well - but were not included in this study. He has made consistently accurate predictions during boom and bust cycles.
Disregard Paul Krugman's economic analysis and predictions, just because you disagree with him on policy, at your own peril.