Flexible working and better performance assessment are key to retaining more women in law, according to a recent survey by the Law Society and LexisNexis.

The survey, published to coincide with International Women's Day today (8 March), canvassed 1,144 respondents, with flexible working options and performance metrics that allow for fewer hours in the office cited as the best ways for the legal profession to retain more women.

Respondents said the primary reason more women do not reach senior positions in law is the difficulty in balancing career and family, followed by the profession's long hours culture. Other problems highlighted include resistence to flexible working and unconscious bias.

Nearly two-thirds of respondents (64%) said gender diversity was an important commercial issue for their firm. While it would be unlawful for firms to operate a quota in order to improve diversity, 40% of respondents would personally support such a move, with nearly a third believing quotas to be necessary in order to achieve diversity in law firms.

Figures from the Law Society's annual statistical report published earlier this year show the number of women in law tails off significantly after the age of 35, despite the fact that over the last 10 years women have accounted for more than half of new entrants to the profession.

One survey respondent said: "A cultural change is required and would not happen without quotas – the numbers coming out of law school and starting in the legal profession have been at least 50% female for some considerable time now, but this is not at all reflected at senior levels within the profession. It was previously thought that this would change with time but it has not done."

A number of law firms have recently made efforts to increase the number of women in their partnerships and management roles. Ashurst has introduced a target for the number of women it wants to employ in management positions, with the City firm aiming to have one quarter of its management posts filled by women within the next three years.

Meanwhile, Freshfields Bruckhaus Deringer also rolled out unconscious bias training to its partners firmwide in a bid to increase diversity within its ranks.