&quot;So what use is economics to politics? When the White House calls to ask how many jobs its agenda will create, what should the humble economist say? “One answer,” Mr. Roberts suggests, “is to say, ‘Well we can’t answer those questions. But here are some things we think could happen, and here’s our best guess of what the likelihood is.” That wouldn’t lend itself to partisan point-scoring. The advantage is it might be honest.&quot;