The study has been used by politicians in the election campaign to turn up the heat on the basics but was based on a sample of primary 5 pupils in spring 2001, just over two years after the national drive on literacy was fully implemented.
Evidence of more sustained progress in improving standards of reading and success in narrowing disadvantage has only recently emerged from studies in Inverclyde, Glasgow and Aberdeen - several years after the introduction of revised literacy approaches.
The first national Scottish evaluation of early intervention noted improvements in infant reading but no narrowing of the gaps evident from the first days in P1.
Only last month, ministers trumpeted the success of Clackmannanshire's "synthetic phonics" approach to early reading which is said to be making dramatic gains. By P6, girls are reading 23 months ahead of their chronological age and boys a staggering 31 months.
All 19 primaries in the authority deploy the strategy which teaches sounds for letters.
Such advances may not have been picked up by the Progress in International Reading Literacy Study (Pirls) test, Scottish Executive sources suggest.
But Scotland's less than glorious placement of 14th out of 35 countries worldwide does reflect the concerns of HMI about the lack of progress in English language between P5 and S2.
The inspectors' report, published in March and based on school inspections between 1998 and 2002, highlighted problems with spelling, punctuation and syntax. There was sterling work in the early years but progress tapered off around P5. By P6 and P7 there were problems with reading and writing.
Similarly, the results of the Assessment of Achievement Programme, published alongside HMI's verdict, highlighted worrying dips in language performance in upper primary.
Following these reports, Cathy Jamieson, Education Minister, unveiled a literacy strategy involving secondaries and associated primaries which will review reading and writing approaches between P6 and S2.
A national advisory group will begin its work in August. Ministers have also dispatched a report on synthetic phonics teaching to all schools.
A further strand is the launch of the home reading initiative last August and the appointment of two development officers to encourage children and parents to read together at home.
These initiatives should help Scotland to lift language attainment in P5 and above when the next AAP English survey is rerun in 2005, it is suggested.