It depends, of course, what assumptions you have made about Plowden, and about the lasting effects - or otherwise - that the report had on the nation's primary schools. Of course it wasn't just about child-centred discovery methods and the end of rote learning, but how much of the thinking identified with her name really changed the system? And how many people got it right?
One answer is that, like so many seminal publications, everyone takes from it the ideas that they fancy and ignores or misinterprets the rest. Another is that no report, however powerful in its provenance or popular in its appeal, is really likely to revolutionise teaching methods in the short or medium-term.
Perhaps because the 1967 Plowden report was so swiftly followed by the Black Papers, it was also named and blamed before long for the trendy teaching methods that traditionalists claimed had reduced primary teaching standards to ruin. But when Professor Neville Bennett researched teaching styles and pupil progress nearly a decade later, he found that teachers were still just as likely to be using formal traditional methods as progressive Plowden styles, and that the teachers with the best results used a mixture of both.
The phoney progressive-traditional battle was still being waged in 1991 when Professor Robin Alexander reported on a Leeds project designed to shake up the city's primary schools. Among many problems peculiar to Leeds and an over-powerful advisory service, his most illuminating finding was that the outward trappings of the post-Plowden classroom were no guarantee of good practice, if not enough learning was going on behind them.
Grouping, good display, enquiry methods and a seamless curriculum would not in themselves raise reading stanards or combat failure if teachers did not know how to manage these more demanding settings, or to combine a caring environment with mastery of basic learning skills. You had to look at what was going on behind the label.
It was a verdict that proved equally true of the rest of the country a couple of years later when Alexander, along with primary chief HMI Jim Rose and Chris Woodhead (then of the National Curriculum Council) conducted a national primary review. By then we were into the national curriculum, subject specialism was forcing out unstructured topic work, and a judicious mix of whole-class teaching, groups and setting was emerging as the accepted wisdom. We have galloped down that road since then.
Now the combination of national initiatives and relentless inspection can both open up what is going on behind the labels and ensure that something does happen in the first place. Where Lady Plowden and the Central Advisory Council for Education could research, visit, enthuse, innovate, proselytise and influence England's primary schools, even the last of the great and the good did not have the power to make things happen to order. Nor indeed did the Department of Education and Science some 30 years ago. Transmission of the message depended on the agenda and the perceptions of LEAs, teachers and their trainers.
The present Government has a firmer grip on universality. When it introduced its literacy and numeracy hours, armies of advisers and private contractors were deployed, and teachers from every school earmarked for training. Targets, inspection and performance management check out that what they say is what we get.
All the same, Plowden ideas like educational priority areas, parental involvement, universal nursery schooling and an end to corporal punishment have all prevailed, one way and another. And her thoughts on teaching style have not all been thrown out of the classroom window, thank goodness.