More town halls will be rapped by the government for failing to track what happens to teenagers after they leave school.
Skills minister Matt Hancock will write to nine local authorities who have no idea whether large numbers of 16 and 17-year-olds in their area are still involved in education or training.
Councils were handed a new duty to measure whether 16-year-olds are still in learning, ahead of the raising of the threshold to 17 from last September. But a Department for Education study found startling variations in the proportion of teenagers unaccounted for in local authority records - with poor IT systems thought to be to blame.
Some of the worst offenders criticised last autumn - such as Poole, Derby, Waltham Forest, Herefordshire and Derbyshire - have now upped their game.
Hancock said he was still alarmed by "a further nine underperformers", in the latest statistics issued by the department for education (Dfe), covering up to the end of 2013. The minister did not reveal the latest poor performers, ahead of writing to them, but those with deteriorating records - between last June and last December - include:
* Worcestershire - proportion of 16 and 17-year olds classed as "activity not known" up from 4.7% to 26.5%
* Croydon - up from 11.1% to 21.6%
* Rutland - up from 8% to 18.9%
* South Gloucestershire - up from 7.1% to 14.8%
* Lewisham - up from 4.5% to 12.7%
* Lambeth - up from 4.3% to 12.3%
Hancock has stressed that "you can't manage what you don't measure", reminding town halls that they now have a "duty to collect this crucial information."
However, overall, the minister said he was pleased with an improving performance, with a rise of 35,482 in the number of 16 and 17-year-olds in education or training, across England.
That came as a relief to ministers, because they have been fiercely criticised for stubbornly high levels of long-term youth unemployment, risking a 1980s-style "lost generation".
Hancock insisted government measures were reaping rewards, including new traineeships and an expansion of apprenticeships."More young people in education or training is welcome news. This shows good progress," he said. “We have a clear programme of reforms to improve the quality of young people's education to ensure, through traineeships and apprenticeships, that all have the chance to reach their potential."
