The argument that current monetary policy in Japan is in fact quite accommodative rests largely on the observation that interest rates are at a very low level. I do hope that readers who have gotten this far will be sufficiently familiar with monetary history not to take seriously any such claim based on the level of the nominal interest rate…. A more respectable version of the argument focuses on the real interest rate…. [T]oday’s real interest rate may not be a sufficient statistic for the cumulative effects of tight monetary policy on the economy…. [O]ne might want to consider indicators other than the current real interest rate—-for example, the cumulative gap between the actual and the expected price level—-in assessing the effects of monetary policy.
And if we apply Bernanke-1999's test applied to the U.S. economy today, we see a deflationary gap.
This deflationary gap is what Scott Sumner means when he claims that Bernanke's monetary policy has been "tight". This is what Ben Bernanke-1999) would be referring to were he--as he would--claim that Bernanke-2012's monetary policy is "tight".