By Sean Coughlan
BBC News education reporter
The test results show a strong link between poverty and low achievers
Among those 11-year-olds who failed to reach the expected level in their English tests, 84% were classified as either having special needs, English as a second language or else qualified for free school meals.
These figures show that among the one in five pupils who failed to make the grade in this subject, there was an overwhelming link to either special needs or poverty.
In the rest of the cohort - those without special needs, those not eligible for free school meals and those who do not have English as a second language - the success rate in reaching the expected level is almost 97%.
These details are from an analysis of last year's primary school results, when 20% of pupils failed to reach the Level 4 in their English tests.
This level of detail is not available yet for this year's tests, but there is once again a similar proportion of pupils failing to reach this benchmark, only slightly lower at 19%.
With warnings that the results show that once again one in five pupils is leaving primary school without achieving the basics of reading and writing, who are these struggling children?
WHO MISSES THE GRADE?
Among those not reaching the grade for English:
59% have special needs
26% free school meals
14% do not have English as a first language
Boys more likely to be low-achievers - 26% compared to 15% of girls
Regional variations - between 11% and 30% missing the grade
Ethnic minorities - 28% of black pupils below benchmark compared to 20% of white pupils
Among this low-achieving fifth of primary pupils, 59% had special educational needs, 26% were eligible for free school meals and 14% had English as an additional language.
Only 16% of the pupils who did not reach the benchmark in English were not classified in at least one of these groups.
The government has once against missed its target of 85% of pupils reaching this expected level in English - and this analysis shows that to reach such a target will mean raising results within these groups.
There are other characteristics within this group of low-achievers.
They are substantially more likely to be boys than girls. In this year's results, 26% of boys failed to reach Level 4 for English, compared with only 15% of girls who did not make the grade.
There are also regional variations - ranging from areas in which only 11% in total do not make the grade down to those in which 30% miss out.
At the upper end is Richmond-upon-Thames in which 89% of pupils (91% of girls) achieve the expected grade - down to the lowest local authority score of 70% for pupils in Southampton (64% for boys).
Ethnic background is another factor. For last year's results for English, 80% of white pupils reached the expected level, the same as the national average, while the figure was 72% for black pupils.
Many of these factors can overlap - compounding the statistical likelihood of being in this low-achieving group.
Given that only 3% of pupils do not make the grade among those who do not have special needs, free school meals or English as a second language - it means that any improvements in annual results will have to address such multiple challenges.