In the Dark Ages, the test to determine whether you made the grade as a witch amounted to being dunked into water.

Trial by drowning for lawyers was outlawed at the end of the last century and law firms now have to make do with the interview process to weed out unsuitables.

However, law firms seem to be increasingly questioning its usefulness as a sole determining factor in hiring, and are often turning to psychometric testing as a recruitment tool.

Today, psychometric testing splits into essentially two types - ability and personality.

Cynics question whether psychometric testing is better than gut instinct.

Advocates point out that its objectivity gives increased certainty and fairness to the recruitment process.

Antonia Fowell, a resourcing consultant with southern firm Bond Pearce, is convinced of the merits of ability testing for lawyer recruitment.

She says: 'Interviewing is an imprecise science and the use of appropriate tests can be a valuable and objective complement to the selection process.' Bond Pearce, which has successfully used ability tests in graduate recruitment for several years, is now expanding their use into other areas of recruitment and career development.

Birmingham-based Wragge & Co is considering making increased use of questionnaires, having traditionally only used them for some training and development purposes, preferring practical rather than psychometric questioning to evaluate candidates.

Content that knowledge and skills can be assessed at interview, the firm is turning attention to personality to help predict future performance.

Recruitment manager Charlotte Hurley explains: 'Effective performance at team and individual level can be influenced by personal style.

Psychometric questionnaires could offer greater insight into typical or preferred behaviours than traditional questioning alone.'

Certainly not all firms are believers in the tests.

Louise Hadland, human resources director at national firm Shoosmiths, describes why her firm no longer uses ability testing in recruitment: 'It was easy to fixate on the results because of the ease of comparison, rather than looking at the bigger picture.

We also questioned whether a candidate's test results could be more informative than a decade of examinations and qualifications.'

Applicants are often critical of psychometric testing, or perhaps scared of a test that is difficult to prepare for.

The good news for candidates is that law firms are only using psychometric testing to complement traditional recruitment methods, rather than as a substitute.

Lyndon Jennings is a recruitment consultant at Taylor Root in London