A significant underperforming tail remains but the majority are well ahead of their chronological age in word recognition and spelling. This strengthens the evidence produced two weeks ago in Aberdeen that early intervention is beginning to pay off.
Results from the sample of P6 pupils who began school in 1996 show for the first time that the expected dip in performance as pupils move through primary is no longer evident. Teachers in the study schools have revised their reading and writing strategies and carried on the progress that is well established in P2 and P3.
Further analysis suggests this is continuing into P7, a major Scottish first for a city often publicly attacked for appearing to fail large numbers of children.
Alan McLean, Glasgow's principal psychologist, who conducted the study among 730 pupils in 24 primaries - 9 per cent of the cohort - hailed the results as conclusive confirmation that early intervention was effective.
Most P6 reading levels achieved or outstripped the United Kingdom for the age group, proving that schools can overcome the effects of high deprivation. Some primaries do exceptionally well and perform well above UK standards, others less so, underlining that individual schools also make a difference.
Among other significant findings is that differences in pupil ages, which can vary by as much as 18 months, affect levels of literacy in P6.
"Teachers therefore need to be aware of the age differences in their class, particularly at the later primary stages," Mr McLean said.
There is no significant difference between older and younger children in P1 but by the time they reach P5 the older group moves ahead by six months in reading. This continues into P6 with the older group "superior in decoding by eight months and comprehension by seven months. Spelling was also six months ahead."
Mr McLean said there was "stunning" evidence that the 35 per cent of pupils who switch schools between P1 and P6 score markedly lower. "By P5, children who moved into and out of the schools had an average reading age 10 months below the stable group. This pattern is repeated exactly in P6."
Girls continue to do better than boys after starting off primary on a relatively equal footing. By P2, they are leaping ahead and the trend continues into P6. They are better at spelling and writing, although the difference in reading is less notable.
The city's poverty legacy remains in reading comprehension with 24 per cent of the age group in P6 remaining below the P3 level. On a positive note, a similar percentage are above the P7 level.