From the article:
When foreign aid enters developing countries, it is welcomed with handshakes and ribbon-cutting. Private money, by contrast, is sometimes smuggled across borders or siphoned into offshore bank accounts. Everyone agrees that such “illicit financial flows” are a problem. A report published on January 28th by Global Financial Integrity (gfi), a campaign group, estimates that illicit flows to and from developing countries are worth more than a fifth of their total trade with the rich world.
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Obviously, gun-running and drug-trafficking should count; in 2011 the unestimated that financial flows linked to transnational organised crime were worth 1.5% of global gdp. Bribes, and the proceeds of unregistered trade in legal goods, such as cigarettes, probably should, too. But broader definitions also fold in tax avoidance, which may not be illegal. The result is hopelessly vague, diverting attention from dirty money to smear legitimate businesses, argues Maya Forstater of the Centre for Global Development, a think-tank in Washington. Tax activists retort that the line between lawful and unlawful acts is often blurry. Developing countries lack resources to pursue complex legal cases, so big firms find it easier to get away with avoidance that should count as evasion.