Girls Aren't Bad At Math

(edited and partially rewritten for coherency)

but Megan is.
Sayeth the Krugman:

The predicted impact from the stimulus is indicated by the difference between these two curves. We're now at the very beginning of 2009Q3; they predicted that the unemployment rate right now would be only a fraction of a percent lower now than it would otherwise be. The impact wasn't supposed to be really noticeable until late this year, and wasn't supposed to peak until late 2010.

Which is to say the rate of unemployment was expected to continue to rise, but at a reduced rate, up until right around this very moment. And, of course, the unemployment numbers we have now represent what has already happened, in the tail end of Q2. If there's a reduction in effect, we'd only just be gathering the numbers that would reflect it. We don't know whether the predictions made by the paper containing the graph are accurate, yet.
Megan has trouble with that part;

But when I look at the graph, it looks to me as if the stimulus was supposed to affect the unemployment rate immediately. Specifically, it was supposed to dramatically lower the rate of increase in unemployment immediately. By now, at the beginning of Q3, unemployment was supposed to start falling. But unemployment has continued to rise apace. It definitely isn't falling.

Another way of reading the graph is to say unemployment was expected to peak very near the beginning of Q3, then begin to decline. She's quibbling, at the moment, over a matter of weeks, in the most charitable interpretation. Megan is simply a bad propagandist. She's knee jerk anti-stimulus (it is big gubbermint, after all), so no matter what, it's not working, end of story. And Krugman is the dumb one, not Megan. She actually wrote the following;

Also, I don't understand what he's trying to get at when he says that unemployment was only supposed to fall by a fraction of 1% by now. In my experience, "a fraction of one percent" is usually used to refer to a small fraction of one percent, i.e. a trivial number. As "fractions of 1%" approach 1%, it gets increasingly hard to distinguish them from 1%, because of measurement error inherent in collecting economic data.

But this fraction is certainly not trivial. Eyeballing it, it seems to be in the neighborhood of .7%.

That fraction is totally not a fraction, you guys, and Krugman is dumb for using the word properly. And let's revisit the line that's confusing Megan; "they predicted that the unemployment rate right now would be only a fraction of a percent lower now than it would otherwise be." Anyone else having trouble parsing that? Unemployment was not expected to fall substantially, immediately, it was expected to be lower than it would have been without any stimulus. I'll let Krugman take it from here;

The problem, in other words, is not that the stimulus is working more slowly than expected; it was never expected to do very much this soon. The problem, instead, is that the hole the stimulus needs to fill is much bigger than predicted. That — coupled with the fact that yes, stimulus takes time to work — is the reason for a second round, ASAP.

Krugman has been criticizing the stimulus plan for not going far enough from the very beginning, while yes, defending it from dishonest critics like Megan, which means he's being consistent and careful in his treatment of the topic. When Megan said;

Paul Krugman is a very smart economist, far smarter than I am. So when I do not understand this post, I assume that I must be missing something.

she was giving herself too much credit. The problem is not economics, the problem is basic grasp of English. Too bad Megan spent all her time buried in economics books in undergrad, some English classes might have come in handy.
Oy.