MAKE poverty history is a compelling slogan. Halve it by 2015, in contrast, is a measurable commitment. That is the logic behind the Millennium Development Goals (MDGs), a host of targets in the struggle against global deprivation, disease and illiteracy, set by the world's leaders at a United Nations jamboree in 2000.

The goals claim to convert campaign slogans into bankable pledges, complete with a number and a date. The world has, for example, resolved to cut the rate at which mothers die from child-birth by three-quarters from 1990 to 2015. The percentage of people without safe water will fall by half; infant mortality by a third. Quick to spot a resonant date in the calendar, the UN has declared Saturday July 7th as the official halfway point towards these 2015 deadlines.

The 2000 summit was unprecedented in its pulling power, attracting more bigwigs than ever before. Although many of the targets were recycled for the second or third time—the 1980s were supposed to bring water and sanitation to the great unwashed; the 1990s were supposed to provide “education for all”—they have remained surprisingly conspicuous, becoming a kind of secular scripture for the aid fraternity. The UN family, of course, cherishes them. The World Bank invoked the goals last month when pitching for an infusion of $32 billion from its richer members. Pascal Lamy, head of the World Trade Organisation, followed suit in his plea this week to save the Doha round of global trade talks. Even the IMF, which knows an inconvertible currency when it sees one, pays them solemn respect. And it gives politicians in poor countries more motivation to pay attention to saving mothers from eclampsia or children from diarrhoea.

Sadly, however, they cannot do what they purport to do, which is to provide credible benchmarks against which governments can be judged. Set for the world as a whole, the numerical targets do not fit any country in particular. China had all but met the target of halving poverty from its 1990 levels by the time it was set a decade later. That (plus growth in India) mostly explains why the world is making unprecedented progress against poverty. Almost 32% of people in the developing world lived on less than a dollar a day in 1990. In 2004 that figure was 19.2%. It should fall below 16% by 2015.

Sub-Saharan Africa, on the other hand, will fall short of all of the goals, even though its economy is growing quicker than it has for a generation and it is putting children in school faster than any other region. The extreme-poverty rate in Africa has fallen from an estimated 46% in 1999 to 41% in 2004, but that is still way off the 2015 target of 22%. Hunger and malnutrition still gnaw at the region: the proportion of under-fives who are underweight has declined only marginally, from 33% in 1990 to 29% in 2005. Africa lags partly because its population is growing so rapidly. Thus, although millions more African children are going to school, there are still very many who are not. According to the UN, in 1990 there were 237m Africans under 14; today, that figure is 348m, and by 2015 it is expected to top 400m.

Some goals cannot be met, others cannot even be measured. Poor countries collect no reliable numbers on deaths from malaria or from childbirth—although the goals are helping to stir a welcome interest in generating better figures. And sometimes what is measured (number of children enrolled in school) is not what counts (the number who learn anything).

Foreign aid, of course, does not always produce results, although better targeted funds may produce better outcomes. And some results do not require much money. Brazil is four times richer than Sri Lanka, but its children are more than twice as likely to die before their fifth birthday. Improving sanitation is about breaking habits as much as building latrines. And although aid money can send a doctor to the boondocks, it cannot make him show up to work. The social progress envisaged in the 2015 targets requires the kind of nationwide nannying that only an accountable domestic government, not a distant foreign donor, can sustain.