The 22 unitary authorities, set up in 1996, also struggle to provide an adequate advisory service, with gaps in some subject areas in at least half the authorities. And few are making enough use of information about their schools' performance to target resources on those most in need of help.
Nonetheless, standards in all 22 authorities rose between 1996 and 1998, the inspectors report.
Susan Lewis, the chief inspector of schools in Wales, said last week: "Much of this improvement is attributable to the work of schools themselves. But specific LEA initiatives and actions have also played their part."
She warned, however, that much remained to be done if national targets were to be met, especially at key stages 3 and 4. Authorities must use a mixture of pressure and support in the schools most in need of improvement and spread good practice.
The survey can be obtained from OHMCI, Phase 1, Government Buildings, Ty Glas Road, Llanishen, Cardiff CF14 5FQ (tel: 029 20326839 20325000)