Five years is fair enough
If so, what time is needed to tackle other areas of under-achievement? From Sure Start for under-fives and Reading Recovery for infant pupils to 14-19 reforms and second-chance skills training for adults, multi-million-pound government initiatives abound.
Here, ministers have an eye to the long game. Sharp criticism of Sure Start in March was rejected as "premature" by the then children's minister Margaret Hodge, who secured yet more cash for the scheme.
But when it comes to individual school or college inspections, Ofsted is less forgiving, as Mr Falk found this week. It is easier to defend shortcomings in big initiatives than failings in institutions.
The spotlight is also on academies, because an average pound;23 million a time is spent setting them up. Is it right to throw big cash at seemingly intractable problems?
The answer, in part, is yes. Considerable educational gains have been made in the past two decades. The proportion of 16-year-olds with at least five GCSE grades A-C or equivalent rose from around 20 to more than 50 per cent.
In the 1970s, the idea of getting half of all young people into higher education was a pipe dream.
We are left with the rump of underachievement, which the West London academy and initiatives such as Reading Recovery have to tackle. Common sense says these problems are costly and time-consuming.
But is money going where it should? Swish new buildings won't stop schools failing, any more than fine estates will banish deprivation. While such investment is important, pupils still carry the same social baggage.
Youth, social services and community support need more money. Ministers insist this will come but there is a way to go. From this perspective, five years to turn around a failing school seems a very reasonable request.