The publication of the Panama Papers on April 3 caused a huge stir.1 Much outrage was expressed. In Britain the revelations chimed with a political mood that seemed sickened by growing financial inequality. Thousands of headlines focused on the names caught in the headlights. The prime minister of Iceland was forced out of office. Vladimir Putin, strangely, confirmed the accuracy of the reports, while stressing that they showed no illegality. Assorted celebrities came up with varying responses explaining away their investments—with varying degrees of plausibility. The question that arises over the 11.5 million Panama Papers—all from the Mossfon law firm in Panama City—is whether they will lead not only to prosecution but to effective prevention of attempts to avoid paying billions in taxes. Under current law, many of the dummy corporations are legal, as is the establishment by large US companies of branches in countries with lower taxes.

I asked Gabriel Zucman, author of The Hidden Wealth of Nations: The Scourge of Tax Havens (2015)2 and assistant professor of economics at the University of California at Berkeley, what new things he had learned from the Panama Papers.

“In terms of the structures or mechanisms, nothing,” he told me. “That doesn’t mean that these types of revelations are not important or useful. I think they are very important and critical in generating change, in forcing governments to think harder about this problem of tax havens and to improve their policies. But there’s nothing that’s particularly new.

“You can’t learn anything about the magnitude of the problem from just leaks from one firm, or even a couple or three or four firms—you know, it’s just too limited. And even if you have gigabytes of data, since they only involve one particular firm in one particular country that’s involved in one particular form of tax haven activity, there’s no way to make meaningful inference from that as to what’s the scale of the global problem, the magnitude of tax avoidance and tax evasion, the costs for governments.”

For Zucman, the significance of the publication lay in the response: “I was more interested in seeing the reaction, the global outrage that these documents generated. I think it’s the first time that there is public outrage on such a scale. At the global level people felt very strongly that…