Figures from Birdsong Consulting, which will be unveiled tomorrow, show that 81 per cent of staff in the first year of employment would recommend their employer.
The figure drops to 68 per cent in year two, rises to 70 per cent in year three and drops again to 62 per cent in year four. After year four, the figure gradually climbs back towards year-one satisfaction levels.
The results were taken from a survey of more than 700 voluntary sector employees. Frances Hurst, co-founder of HR specialist Birdsong Consulting, said the figures demonstrated a need for managers to pay close attention to the concerns of staff with three years' service.
"That is the time when senior managers and HR professionals need to be on the case and seek out the concerns of those people and address them," she said.
Maria Aguilar, director of consultancy the HR Services Partnership, said people moving on after a few years could be positive for the organisation.
"People leaving after being in their posts for about four years is not necessarily a bad thing," she said. "Organisations need a bit of fresh blood now and then."