Membership of trade unions steadily increased between 2017 and 2020, driven by a large increase in female membership, according to new research by Durham University Business School.

The study, conducted by Professor Richard Harris and Dr John Moffat, sought to identify the reasons why there was not only an increase overall, but specifically within the female workforce.

The rise in membership, between the years 2017-2020, marked the first sustained increase in membership since 1979, with union membership having fallen into steady decline over the last four decades.

To conduct their research, Professor Harris and Dr Moffat used data from the Quarterly Labour Force Survey (QLFS), carried out by the Office for National Statistics (ONS). Using this database, the researchers were able to conduct a ‘deep dive’ into the changes in trade union membership between 2017 and 2020, and identify the key changes in the workforce which have driven the increase in membership.

The study revealed that, during this time period, whilst trade union membership grew from 6.2 million to 6.6 million in the UK, there was a 0.8 percentage point decrease in the share of male employees who belong to trade unions. In contrast, the corresponding share for females grew by 1.6 percentage points so that, in 2020, women accounted for 57% of all trade union members in the UK.

The researchers state that the rise in female membership of trade unions is due to a variety of different factors.

Firstly, the number of people employed in the more unionised public sector increased between 2017 and 2020. Secondly, there was an increase in the number of men moving roles to non-unionised occupations, whilst more women were shifting to unionised occupations.

The researchers also state that factors such as an increased levels of education, especially for women, as well as an increased rate of working full-time, led to a rise in trade union membership.

However, there is no suggestion that overall trade unions became generally more popular. Instead, the researchers suggest, an increasingly better educated workforce is likely to increase youth membership within trade unions, which can be seen as a positive for workforce progression and campaigning.

The researchers say these findings give food for thought for both trade unions, their members and the stakeholders that interact with them.

“In terms of the prospects for the trade union movement, our results offer reasons for both hope and concern. The increase in union density cannot be attributed to a longer-term underlying trend (perhaps relating to the political climate or changing attitudes towards trade unions) that has increased the attractiveness of unions and which might continue in future years. Instead, the results suggest that whether union density continues to rise after 2020 will be dependent on further favourable changes in employee and their job characteristics” says Prof. Richard Harris

Political changes could also have an impact on membership, according to the researchers. For example, if the government looks to reduce public spending, and therefore the number of workers in the public sector, then trade union membership would be negatively impacted.