"According to Moody's, the ratings agency, the stimulus package has saved more than 500,000 jobs," the often sensible Niall Ferguson writes in the Financial Times this morning. It's not clear what Moody's reasoning is, or how it is better than the reasoning that had the firm placing good ratings on mortgage-backed paper that turned out to be toxic. Moody's is under scrutiny in Washington for the role it and other ratings agencies, which benefit from essentially a government-granted oligopoly, played in the financial crisis. It can only help itself with the Obama administration and with Democrats on Capitol Hill by touting the stimulus as a success. All in all, there's plenty of reason to be skeptical of the claim, not least the statement of President Obama's economic aide, Lawrence Summers: "It is too early to know how successful our policies have been. It is not even clear how we will know ultimately whether they have succeeded, because of the difficulty of constructing a counterfactual and knowing what would have happened without intervention."