Background: Scottish government's 'ambitious' plan to tackle attainment gap questionedpublished at 14:00 Greenwich Mean Time 18 January 2017
Last November a report questioned the Scottish government's ability to close the education attainment gap between rich and poor students.
The Commission on School Reform's challenge paper was concerned the plan was "exceptionally ambitious" and the timescale may be "unrealistic".
First Minister Nicola Sturgeon said improving attainment was a priority.
In September, it was announced that a new system of national testing was to be introduced in primary schools as part of her new programme for government.