The problem, said Lori Taylor, a researcher at Texas A&M University, who was a co-author of the studies, was not with the concept of incentive pay but in the way the program implemented it, with every school choosing its own design.
The British invented planning in its modern form, then implemented it with such ambition and skill that – from Howard's original garden city all the way to the last (and one of the most successful) new towns, Milton Keynes – Britain was the global leader.
The success of an NPI or a set of NPIs depends on both its efficacy and the feasibility of implementing it with relevant populations.
Last month, Zamfara, which had announced its intention of imposing Islamic law in October, began implementing it with the public flogging of a man found guilty of drinking alcohol.
More important, he afterward chose not to go looking for loopholes but to implement it with considerable vigor.
Having run as a conservative, he unveiled a conservative programme and set about implementing it with remarkable efficiency.
The state favors a full day, however, and has tried to encourage poorer districts to implement it with their early childhood grant money.
"At the central level it takes a lot of time to make a decision, but when they do they implement it with force," he added.
Britain has not only imposed one of the highest capital ratios among major rich countries but has implemented it with notable vigour.
This confusion just adds to the government's mounting political disarray - it cops all the flack for sticking with the unpopular policy and continuing to try to implement it, with none of the policy benefits it claims it would achieve.
