The main message from this week's disappointing key stage 2 test results is that school improvement is a bumpy ride. There is no magic formula; no smooth progression to the sunny hills of Targetland. Ministers could have expected good news after last year's rises - but no such luck. This year, they ruefully contemplate a minuscule improvement in English, and a worrying fall-back in maths.
Even the effect of the literacy strategy, on which the Government is pinning its hopes, seems inconsistent. Pilot schools in some authorities have achieved well above the rest - but the reverse is true for others.
However, too many gloomy conclusions should not be drawn from one year's results. First, every teacher is familiar with "good years" and "bad years". This may be an unfortunate blip. Second, the impact of the literacy strategy will initially be felt further down the school. Two and a half terms is a relatively short time in which to turn round 10 or 11-year-olds who have been under-achieving for years.
Third, many complementary policies have not yet clicked into place. If the Government's analysis is correct, a variety of influences combine to create a high-achieving or low-achieving society. Education under Labour aims to ameliorate the damaging effects of a society which has been profoundly unequal for generations.
The marked gap between schools with the best results and those with the worst tends to reflect the gulf between the most and least prosperous and ambitious communities. This is not a get-out clause for schools; but it does need to be more widely recognised that the fashionable input-outcome model cuts both ways.
We know that, given quality teaching, pupils' skills, knowledge and understanding can be effectively developed no matter what their background. But many children experience very negative inputs during their early years - neglect, abuse, stressed parents, bad housing, lack of intellectual stimulation. The huge task of schools in deprived areas is to elicit positive academic results, in spite of the damage which has already been done. Slowly, more and more are achieving this.
David Blunkett has said that he wants to change the culture; to make a real impact on Britain's historic inequalities would be a colossal achievement. Does anyone think it can be achieved through some kind of quick fix?