The TESSHA survey now confirms that secondary schools lost almost four times as many experienced staff by this route as by compulsory redundancies.
"Natural wastage" is the truly inappropriate term used to describe this.
Wastage it certainly is: a wasted opportunity to improve standards and tackle the excessive workloads that deter many from joining or staying in the profession. And the survey makes it clear that it is lack of funding that is giving rise to non-replacement, not falling rolls. Even with redundancies, three out of four are in schools with static or increasing pupil numbers.
All this is the direct consequence of government action - or inaction.
These staff cuts - in the face of secondary pupil numbers expected to rise by 25,000 this year - are the foreseeable but unforeseen result of the rise in employers' pension contributions, the redistribution of central funding away from the high-cost South-east and alterations to the Standards Fund.
All this was done without the elementary precaution of checking the likely impact on schools.
Next year could be worse. Charles Clarke has promised pound;800 million more but that is barely half what headteachers say is needed. The Department for Education and Skills is unable to say convincingly that the heads are wrong since it does not know how many schools are already in deficit - or would be if they had not had back-up reserves this year.
Next year those reserves will be depleted or non-existent. In addition the real costs of the workload agreement begin to bite, especially in primary schools. Schools cannot go on relying on the right staff to leave.
Redundancies will have to rise to maintain the right balance of specialists or to replace experienced staff with cheaper alternatives. More wastage - but there's nothing natural about it.