The S&P Downgrade: Competence and Consequences

I was asked to comment on S&P's downgrade of long-term US debt:

The Consequences of the S&P Downgrade

As I explain, I don't expect much in the way of market or interest rate reaction to the downgrade. Also, I didn't mention this, but S&P's demonstrated incompetence on matters such as choosing the right baseline is another reason to ignore their pronouncement:

I Heard It Through The Baseline, by Paul Krugman: Oh, my. Treasury has a fact sheet explaining that $2 trillion error by S&P; it may sound technical, but to anyone who follows budget issues, it’s a doozy.

When the Congressional Budget Office “scores” policies, it does so relative to a “baseline”... But S&P initially assumed that the debt deal was subtracting off a quite different baseline.

The point here is not so much the $2 trillion, which makes very little difference to real US fiscal prospects; it’s the fact that S&P stands revealed as not understanding basic analysis of budget estimates. I mean, I don’t think I would have made that mistake; real budget experts, like the people at the Center on Budget and Policy Priorities, certainly wouldn’t have.

So what we just saw was amateur hour. And these people are pronouncing on US credit-worthiness?

Donald Marron:

S&P's 2 Trillion Dollar Error: ...The error is understandable but remarkably sloppy for such an important analysis.

The source of the error is painfully familiar to anyone who deals with U.S. budget projections. S&P’s analysts didn’t use the right measuring stick — i.e., the right budget baseline — when analyzing the effects of the recently-enacted Budget Control Act.

In one sense, it’s easy to see how this error happened. Budget discussions are now hopelessly confused by a profusion of different baseline projections of what spending and revenues will look like in the future. ...

But it’s still remarkably sloppy. Budget experts are well-aware of the problem of multiple baselines. Indeed, we all pepper our conversations and analysis with the question “what baseline are you using?” It’s stunning that S&P didn’t have multiple analysts asking the same question to make sure their original numbers were right.

He adds that:

It’s own revised calculations show net general government debt hitting 85% of gross domestic product in 2021 instead of 93%. That’s a big difference. ... S&P was too dismissive in its clarification.

Experts wouldn't have made this mistake. So why is anyone listening to S&P?