Early statistics from some of the UK's largest law firms suggest students from disadvantaged backgrounds are up to 50% more likely to be hired by firms when they are able to consider their performance in the context of their background.

New research from Rare, whose Contextual Recruitment System (CRS) is now being used by 18 firms, shows it is already making a difference to the number of disadvantaged applicants being hired.

The new report – Social Mobility in Graduate Recruitment: Big Data and the CRS One Year On – draws on data from 54,000 student applications and 671 hires across ten top law firms and one public sector organisation that have already been using the new system, which allows firms to see applicants' performance in the context of the performance of their school and their socioeconomic background.

The research found that while average grades of the applicants and those hired was still AAA at A-Level, disadvantaged applicants were 50% more likely to be hired using CRS than they otherwise would have been.

Clifford Chance hired ten candidates from a pool of 26 applications who would never have been selected for interview had it not been for the new contextual recruitment tool.

Commitment and persistence as well as talent – that's exactly the type of candidate we look for

Meanwhile, Hogan Lovells saw a 50% increase in disadvantaged candidates being hired. At BLP, almost a quarter of the firm's vacation scheme students now come from disadvantaged backgrounds.

Tom Astle, graduate recruitment partner at Hogan Lovells, said: "While it is early days for contextual recruitment and we will not have the complete picture until later this year, the initial findings are encouraging. We are very pleased to see that it is already having a positive impact."

Annette Byron, social mobility partner at Freshfields, said: "If a student has academic ability without having had the advantages that others may have had, their results can show commitment and persistence as well as talent – and that's exactly the type of candidate we look for."

Rare's recruitment tool was launched 12 months ago, with firms starting to use it six months ago. So far, the entire magic circle is using it, alongside firms such as Hogan Lovells, Herbert Smith Freehills, Berwin Leighton Paisner and Ashurst.

The research also found that applications to leading firms came disproportionately from the south of the UK and those with more advantaged backgrounds. It found A or A* students from lower performing schools were 15% less likely to apply than the national average.

The research also highlighted the difference outreach programmes can and are making. Tower Hamlets, which because of its location is a major focus for outreach work by law firms and other City employers, is now the fifth most likely London borough to produce applications to law firms using CRS, despite being one of the poorest in London.

Rare managing director, Raphael Mokades, said: "There are clear indications that greater use of contextual data can widen the talent pool and identify graduates who have outperformed their circumstances and might otherwise be missed. This expands the available student base for employers and ensures those with genuinely impressive achievements and potential are not missed, whatever their backgrounds."