The government will miss its target of getting 85% of England's 11-year-olds to pass school English and maths tests, according to a newspaper survey.
The government says tests are raising standards
Results will show a small increase in the proportion of children reaching the level expected, to 80% in literacy and 77% in numeracy, the Independent found.
It received figures from 40 of England's 150 local authorities.
The Department for Education and Skills said people "would not have to wait long for the real results".
Last year, 79% of 11-year-olds reached the required standard in English and 75% in maths.
A DfES spokesman said: "This means that more than 84,000 more children in English and 96,000 in maths are leaving primary school having reached the expected level compared with 1998."
Shadow Schools Minister Nick Gibb said: "The improvement is clearly welcome but we're still a long way from where we need to be.
"It indicates there are still problems with the teaching of reading and, in particular, with the teaching of maths in primary schools."
Pupils in England sit national tests at ages seven, 11 and 14.
This year's results are due to be published later this month.