The graduate student who found some spreadsheet errors in an influential anti-austerity paper discusses what happened. Here is part of the conversation about the process of finding this error:

Q. You say, don’t you, that their use of data was faulty?

A. Yes. The terms we used about their data—”selective” and “unconventional”—are appropriate ones. The reasons for the choices they made needed to be given, and there was nowhere where they were.

Q. And how about their claim that your findings support their thesis that growth slows as debt rises?

A. That is not our interpretation of our paper, at all. If you read their paper, it’s interesting how they handle causality. They waffle between strong and weak claims. The weak claim is that it’s just a negative association. If that’s all they claim, then it’s not really relevant for policy. But they also make a strong claim, more in public than in the paper, that there’s causality going from high debt to drops in growth. They haven’t been obvious about that…

Q. Paul Krugman wrote in The New York Times that your work confirms what many economists have long intuitively thought. Was that your intuition?

A. Yes. I just thought it was counterintuitive when I first saw their claim. It wasn’t plausible.

Q. This is more than a spreadsheet error, then?

A. Yes. The Excel error wasn’t the biggest error. It just got everyone talking about this. It was an emperor-has-no-clothes moment.

This would make for a good case study in a methodology class in the social sciences: how much of this is about actual data errors versus different interpretations? You have people who are clearly staking out space on either side of a policy discussion and it is a bit unclear how much does this color their interpretation of “facts”/data. I suspect some time will help sort this out – if the spreadsheet was indeed wrong, shouldn’t this lead to a correction or a retraction?

I do like the fact that the original authors were willing to share their data – this is something that could happen more often in the social sciences and give people the ability to look at the data for themselves.