This year's targets for five-year-olds are a "nonsense" because of difficulties ensuring the children are assessed the same way across England, according to officials involved in collating the results.
Figures published last week showed that more than half of authorities had missed targets they had set for pupils at the end of their time in reception. Teachers were criticised as the figures suggested that one in seven of the children struggled to write their own name.
But analysis of the local authorities' figures show that wide differences exist between different area targets and results.
The provisional foundation stage profile results - which include figures for independent schools - show the proportion of children who reached a "good level of achievement" at the end of reception this summer. They range from 65 per cent in Richmond to 27 per cent in Barnsley.
More significantly, the local authorities' targets sometimes seem extremely different to the results - partly because they had to set them two years ago after discussion with the National Strategies quango.
Knowsley had outperformed its target by 21 percentage points, it had a target of 29 per cent for 2008, but this year 50 per cent of five-year- olds were assessed as "good".
Hull had a similar gap with a target of 28 per cent and an actual result of 42 per cent. South Tyneside, however, had expected 56 per cent of five- year-olds to do well - higher than the national average - but only 35 per cent did.
Effie Hunt, foundation stage profile moderation manager for South Tyneside, said: "The targets were set two years ago on results which were uncannily high. People had not been trained in the profile and were giving ridiculously high results. We said they were nonsense targets. We have high levels of deprivation among the highest in the country, so you would expect results lower than the national average and hope children gain ground in key stage 2." She said that the 2009 targets were more in line with what was expected and had in fact been met this year.
Similarly, a spokeswoman for Hull City Council said: "The difficulty is the targets were set two years in advance. Last year we would have reset the target. The targets for 2009 are more realistic."
Children who can read simple words such as "red" or "car" and form letters, are regarded as having a good level of language. Those who join in activities and understand why tidy-up time is important, had a good level of social development.
Nationally, 49 per cent of children were seen to have good language and social skills, below the national target of 53 per cent.
The Conservatives said that the figures were "disturbing" and a sign that children's development had slipped back since 2005. The Government says the 2008 data is "sufficiently robust" to publish but the fall in results is probably due to tightening up on moderation.
David Miliband told the Labour party conference that trying to demonstrate the Government's achievements with lists of statistics "doesn't work".