Employees in the public sector do 120 million hours of unpaid overtime a year – the equivalent of employing an extra 60,000 people, according to new research by the Centre for Market and Public Organisation (CMPO) at the University of Bristol.

The study led by Sarah Smith and colleagues, published in the spring 2008 issue of Research in Public Policy, reveals that people working in the public sector areas of health, education and social care are more likely to do unpaid overtime than those in the private sector. This public-service ethos or ‘pro-social behaviour’, whereby employees are driven to serve for the greater public good rather than financial reward, is considered essential for these key services.  Privatisation of these services and the introduction of financial incentives could threaten to undermine that ethos.

The data show that 46 per cent of employees in education, health and social care in the non-profit sector do some unpaid overtime, compared with 29 per cent of their counterparts in the private sector. They also do more hours of unpaid overtime a week (nine hours 35 minutes compared with eight hours 20 minutes).

The ‘pro-social behaviour’ link – the extent to which staff are motivated by the desire to help others – using unpaid overtime as the measure of pro-social behaviour, was calculated by recording the number of hours an employee works without any direct financial compensation.

However, the research revealed that ‘pro-social behaviour’ is not found in all areas of the public sector and there is not a general ‘non-profit effect’. The study found there was little difference between the amount of time worked by people in the for-profit and non-profit sectors in areas other than health, education and social care.

There are differences between workers in the two sectors that may account for this so-called ‘non-profit effect’. For example, after taking into account a wide range of individual and job characteristics – including age, gender, ethnicity, marital status, number and ages of children, contracted hours of work, job tenure, employer size and unionisation – the research still shows that public-sector employees are older and more likely to be female.

The research also finds that there is no change in unpaid overtime behaviour when people move from one sector to another. People do not start doing unpaid overtime when they move from the for-profit to the non-profit sector. Instead, there is evidence that people who were doing unpaid overtime in the for-profit sector are more likely to move into the non-profit sector (and vice versa).