I suppose we should start trying to get ahead of the next GDP report, which most "nowcasting" estimates say will show good growth -- maybe more than 4. This will lead to a lot of stupid commentary; so let's get this chart out there 1/ 
The blue line shows actual quarterly GDP growth since the recovery began; it's a very noisy series, ranging from +5.2 to a couple of negative quarters. The red line shows CBO's estimate of the economy's "potential" growth -- the growth rate consistent with flat unemployment 2/
This tells us the economy's long-run growth rate, since unemployment can't fall without limit. Now, the Trump tax cut is supposed to raise long-run growth -- up to 3 percent or more over the course of a decade. What will one quarter tell us about that goal? 3/
The answer is clear: nothing. 5.2% growth in the 3rd quarter of 2014 wasn't the signal of an upward breakout in long-run growth, just one of those fluctuations which are normal wiggles around the trend 4/
Going further back, Jimmy Carter had one quarter of 16% growth! Remember the Carter boom? Neither do I. So anyone who makes a big deal over this quarter's number is just revealing his or her ignorance. 5/
