South Africa just published the six-question test it wishes it had used in 2001. Any zone authority can copy it.

South Africa put its economic zones on stage in Durban this month, at the second International SEZ Conference, and the headline was a scoreboard. Thirteen designated zones across eight provinces, 224 companies operating inside them, a combined R31.7 billion invested. The more useful sentence was not the boast. It was an admission about what that money actually did, delivered by the two men who run the programme, Deputy President Paul Mashatile and Trade, Industry and Competition Minister Parks Tau.

Start with Coega, the flagship, designated in 2001 as the country's first industrial development zone. By 2010 the government had put more than R3 billion of public money into it and drawn 21 investments worth R9.2 billion, generating 2,837 operational jobs. Then the honest part. Some of those investors were not new. They had moved in from elsewhere in the country, pushed out of their old sites by failing municipal services, and the zone risked becoming an enclave, a well-serviced island cut off from the town beside it. A relocation is not a new plant. It lands in the investment book all the same.

That gap between what a zone reports and what it adds is now built into the programme's own accounting. Tau gave the combined figure as R31.7 billion, then, almost in the same breath, called it a net increase of R17.2 billion over eight years. The R14.5 billion in between is capacity that was already somewhere in the South African economy. Most zone authorities never split those two numbers in public. South Africa did it at its own showcase.

The answer to the enclave problem is a screen. Mashatile said every new zone under the coming Spatial Industrial Development Strategy is tested against six layers before it is sited. Is it on a real infrastructure corridor, with ports, rail and power that already exist. Does it sit near a resource endowment, from the platinum belt to the farming regions. Can it revive an existing industrial park, an Isithebe or an Ezakheni or a Babelegi, instead of pouring concrete on empty veld. Does the district know its own competitive advantage. Do the socio-economic numbers put the zone where the jobs are actually needed. And the last one, the one that answers Coega directly: does the township next door see any benefit, because a zone the surrounding community cannot feel has not done its job.

The measurement is meant to bite. Zone chief executives were told they will be judged every five years on jobs and exports, not on the quality of their brochures. The competitive framing was just as blunt. Something like 5,400 zones are chasing the same capital worldwide, so a mid-sized economy cannot win by being the cheapest address on the list. It wins by being the most reliable and the best connected to what surrounds it. Tau tied that to the trade weather too, arguing that with tariffs and carbon border rules leaning on South African goods, the move is to widen where exports go, not to back away from export-led growth.

For an agency anywhere, the part worth stealing is the self-audit, not the six specific layers. Any zone can post a big cumulative investment figure. Far fewer can say how much of it was capacity the country did not have before, as against firms shuffled across a provincial line for a better-serviced plot and a tax break. The first number grows an economy. The second mostly moves it around. South Africa's contribution this month was to say that difference out loud, and to write the test for it into how the next zone gets chosen.