Olivier Blanchard, the former IMF chief economist, says forecasts for productivity growth are uncertain. Prior to that, Edward Alden, a senior fellow at the Council on Foreign Relations, says the right economic nationalist conversations to be having are those that surround corporate tax reform. Torsten Slok, the chief economist at Deutsche Bank Securities, says we've plucked the lowest-hanging fruit when it comes to the growth outlook for the U.S. Finally, Marc Chandler, the head of currency strategy at Brown Brothers Harriman, says the market's expectation of a March rate hike doesn't change the odds of three rate increases this year.