Welsh schools lost the ability to promote and share good practice after abandoning secondary league tables, according to a leading civil servant.
Chris Tweedale, who heads the Assembly government's school effectiveness group, told the ASCL conference that his department was looking at ways of using data to compare the performance of pupils, rather than individual schools.
Although there is no appetite to reintroduce performance tables, Mr Tweedale said there must be a better way of using data to celebrate success. "We have become frightened of using data to look at what's going well and I think we need to change that," he said.
"It's important to use data properly to the best effect for improving things."
Wales "threw the baby out with the bathwater" when it abandoned secondary school league tables in 2001, Mr Tweedale told delegates.
In contrast, in England everybody knows which schools are successful and what they are doing right, he added.