There are reasons to be cheerful; teacher numbers are up, for starters. But the School Workforce Census for last year shows that recruiting and retaining a top quality workforce is still a major challenge

The School Workforce Census (SWF) is the main source of information on school staffing in England. It provides detailed statistics, such as teacher salaries and qualifications, levels of sickness absence, and the numbers and characteristics of school staff. Collected annually since 2010, the latest statistics relate to the workforce of 21,728 state-funded schools in November 2014. Only 93 schools failed to submit usable information, meaning the statistics should be very reliable.

The data holds some good news – absolute staff numbers are going up, for instance. There are more teaching assistants and non-teaching support staff, while the number of teachers has increased 1.2 per cent since 2013 to 454,900 full-time equivalents.

The biggest concern is the number of teacher vacancies

Most of this increase is in the primary sector. Primary teachers will benefit from the continued decline in pupil-teacher ratios (20.3 in the maintained sector and 20.8 in academies).

Secondary teachers continue to enjoy a lower average pupil-teacher ratio of 15.

Teachers are well qualified, with the overwhelming majority (96.6 per cent) holding qualifications at degree level or higher. More time is being spent teaching EBacc subjects (57.8 per cent of teaching time in 2014 compared with 56.6 per cent in 2013).

Unfortunately, the bad news outweighs the good. The biggest concern is the number of teacher vacancies. There were 1,030 vacant posts in November 2014 compared with 750 in November 2013, so even though there are more teachers, there are relatively more unfilled posts. A further 3,210 full-time posts (0.9 per cent) were being temporarily filled by a teacher on a contract of at least one term but less than one year, almost 1,000 more than in 2013.

Finding appropriately qualified staff is more difficult in secondary schools, with fewer English, maths and science teachers holding relevant post A-level qualifications for the subjects they teach. This has led to fewer lessons in these core subjects taught by teachers with relevant qualifications.

Secondary schools also employ the majority of unqualified teachers (57 per cent – 11,500); primary schools have just over half as many unqualified teachers (29 per cent – 5,900). In combination, these secondary phase statistics are cause for concern, especially as state-funded secondary pupil numbers are projected to increase again after 2015.

The ugliest news is the striking 15.4 per cent of teachers in free schools who are unqualified (compared with 4.5 per cent of the maintained sector and 5.8 per cent in academies). This could be due to the way growing numbers of Teach First and School Direct teachers are recorded. The rise in unqualified teachers (4.5 per cent compared with 3.7 per cent in 2013) could be part of the reason the average classroom teacher salary (£34,300) went down by £100 in 2013.

Over the same time, the average salary of leadership group teachers (£56,500) increased by £500. This seems pretty unfair – why aren’t classroom teachers getting pay rises at the same rate as school leaders? The pay gap between classroom teachers and leaders is greater in academies than in maintained schools. This reflects the general salary gap between the sectors, with primary teachers in academies earning, on average, £1,500 less per year than their colleagues in the maintained sector (the secondary gap is an annual £1,200 in favour of the maintained sector).

One final ugly statistic is that 55 per cent of teachers had at least one period of sickness absence during the 2013/14 academic year. Issues around teacher workload and stress are well known and likely to have contributed to the total of 2.21 million days lost in 2013-14 – an average of 4.3 days for every teacher. This is around the UK labour market average of 4.4 days per worker, although teachers’ working days are concentrated within fewer months of the year, indicating higher average sickness rates.

Taken together, the latest statistics show recruiting and retaining a top quality workforce is still a major challenge for many school leaders.