It is also a reminder that HMI - Ofsted's crack team - are still in business, and of their unique ability to select evidence from any part of the school system, and to analyse it without deference to local hierarchies.
Newspaper reports when the survey was published in December picked up the weakness in the work of some teaching assistants, who were taking the main responsibility for hearing children read without the skills they needed to do it.
Higher up in HMI's main findings, though, was some headteachers' lack of understanding of the teaching of reading and a failure to provide decisive leadership. Only HMI could, or would dare to, make a professional criticism of this magnitude. Now that they have made it, it needs to be followed up.
HMI also highlight the importance of effective teaching, of identifying and tackling problems as early as possible, and of "rapid, early coverage of phonic knowledge and skills" to provide "a strong foundation for decoding".
A key element is the development of children's ability to apply their phonic knowledge in reading new words by blending sounds.
Children in less effective schools had some knowledge of initial letters "but did not have the skills to blend sounds together to produce the correct word". This blending is at the heart of what has come to be known as synthetic phonics - the synthesis is in the building of the word from the sounds.
HMI's evidence is that this form of phonics is essential, but that it is not the whole story. Good phonic knowledge helped children to decode new words, but did not always help them to understand them.
They stress the importance of reading all of the letters in a word, rather than getting the first half right and guessing the rest, and encourage the use of a wider range of strategies. However, these are not all equal. HMI put strategies in a clear order of importance, with context used to check rather than as the main strategy for reading a word.
Enjoyment of reading receives equal status with teaching techniques. This is founded partly on evidence from international surveys that the UK has a higher failure rate than other European countries, and that boys tend to have poorer attitudes than girls. The basic picture is that the better pupils read, the more they tend to like it, and vice versa, much like the golfer who got luckier the more he practised.
Weaker readers tended to find themselves confined to a narrower range of books. As one bored Year 3 pupil put it: "My book just has 'Look, Look!' in it. (He rolls his eyes) What use is that?" This section of the report puts HMI squarely in the real-books lobby.
On the other hand, if HMI's evidence-based approach gives authority to their findings, it also limits the scope of their work to what is already established. Important as this paper is, most of the ideas it contains were current in the ongoing reading debate 15 years ago.
They note that the long tail of under-achievement is common to all English-speaking countries, but their methods do not allow them to investigate the obvious question of whether this has something to do with English itself, whatever teaching methods are used.
The point here is not whether English is more awkward than other languages - French has large numbers of letters at the ends of words that are not pronounced - but where the irregularities are. In English, they affect many of the most common words: do, to and who, for example, require us to abandon the normal sound of the letter "o".
The implication is that, in order to use phonics effectively, we don't just need to repeat or blend what the letters tell us, but to interpret it. In Finnish, by contrast, everything you see is an exact representation of sound patterns, with the result that Finland has never had any problems with reading since international investigations began, and never seems to have any arguments about teaching reading.
To date, no one seems to have investigated how these skills in interpreting information from letters develop, or how best to teach children who are thrown by irregularity when they try to sound words out. We seem stuck with a choice between telling children just to learn them, or blind alleys, notably the Initial Teaching Alphabet, that tried to make the language more logical than it really is.
My own experience tells me that the issue is central to dealing with reading difficulties, and that explaining irregularity is usually the key to enabling children to make sense of print. It would be helpful to see the issue properly explored.
John Bald is an independent literacy consultant