Otherwise this year's regime of target-setting could become a bureaucratic distraction from the real business of raising standards, said Michael Bichard, the Permanent Secretary who runs the Department for Education and Employment.
"Local authorities need to be careful about the rapid expansion in the data available," he told the Society of Education Officers.
"Schools could spend a year studying data rather than getting on with measures. It is possible for data to confuse rather than clarify. So we have deliberately kept our target-setting regime simple."
He suggested that the business world could offer useful advice on disseminating practical data.