Some law firms are using diversity initiatives to help propel women up the career ladder that are counter-productive, according to early indications from the latest research.

A joint venture project between Thomson Reuters Transforming Women's Leadership in Law (TWLL) and legal research platform Acritas, has begun investigations into the effectiveness of diversity initiatives used by law firms.

The preliminary results, collected by cross-correlating diversity initiatives with female retention rates to understand which initiatives are working, have highlighted that certain initiatives have negative impacts. A key example of this is women-only groups.

Hart Shepherd said while these groups could be detrimental for a number of reasons, she suspects the main problem is that it alienates men, meaning a large number of people at the firm feel excluded from its diversity drive.

Three initiatives that have a positive impact include making it mandatory to have female representation on pitching teams, publicly declaring gender targets, and having a quota for the number of female candidates on partnership promotion rounds.

Acritas chief executive Lisa Hart Shepherd said: "[The project is] about giving leadership and the diversity heads in law firms, and general counsel, some evidence to say, 'these are the things you have to have in place to enable diversity'.

"We want to help the market as a whole to identify something it can truly embrace to encourage diversity."

The preliminary results found that the average proportion of trainees and junior associates that are female is just over 60 percent. Female senior associates make up 58 percent of the total on average, but the proportion of female new partners is just over half this, and women make up just over 20 percent of the overall equity partner pool. Rates vary considerably by firm.

The data so far has been collected from 30 law firms, including three of the five magic circle firms, most of the 'silver circle' firms, and some European firms. The project is now calling for more to take part – especially top 100 firms – during the coming weeks.