Krugman said a fully fledged deflation was very rare.
"If you are only going to get really ... compelled to do something when it turns into a 1933-type deflationary spiral, you are not going to get that and yet you are going to be sitting there with an economy that is persistently depressed, because inflation is too low," he said.
He renewed his call for central banks to target a higher inflation rate than, for example, the ECB's goal of just below 2 percent, to avoid getting trapped in a period of low inflation.
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Olivier Blanchard, the International Monetary Fund's chief economist, had suggested a 4 percent target.
The ECB is preparing a package of policy options for its June meeting, sources have told Reuters, including cuts in all its interest rates and targeted measures aimed at boosting lending to small- and mid-sized firms (SMEs).
Five people familiar with the measures being prepared have detailed plans involving a potential rate cut, including the ECB's deposit rate going negative for the first time, along with the targeted measures aimed at boosting lending to SMEs.
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