After months of searching and exhaustive interviews many companies still find themselves with the wrong recruit. The bright bubbly, dedicated and vivacious character, which they encountered in the interview is but a distant memory.

As many a business person will know, the right staff are the key to success in today's enterprise climate where human resources and skills are central to coping with a rapidly changing marketplace.

Increasingly, employers are looking at alternative ways to assess the suitability of prospective recruits and a 40 minute interview is often insufficient to judge how a person will cope in their new position or environment.

Now both recruitment companies and employers are turning to psychometric tests to get a more balanced view of candidates.

There are two types of such tests: those that aim to measure abilities in areas such as numeracy, problem solving and language, and personality tests, which aim to build a profile of a candidate.

Dr Anne Staunton, an independent psychologist, says "these tests never stand on their own but they are a great additional tool for people assessing candidates because when you're interviewing somebody you're subjective, whereas the test is independent.

"Tests are only useful in the hands of the right people because it isn't easy to interpret them and they can be manipulated by very intelligent candidates who can see the angle of the tests."

Indeed, opinions of the accuracy or effectiveness of testing a person's characteristics through a written survey vary considerably across different sectors of industry and recruitment companies. Mr Mark Parkinson, a psychologist with the Morrisby Institute, which designs and supplies some of the tests available on the market, says "the problem with some questionnaires is that it is fairly obvious what answer the company is looking for and this leads to people giving a false impression of their personality".

"To get around that we put in truth questions such as `Have you ever been late for work?' and monitor the consistency in answers as many of the questions are repeated but just phrased in a different way. "If you then get a series of angelic answers, or if people are inconsistent in their answers you know people are playing the game."

Mr Parkinson claims that personality tests are a more objective means of assessing candidates than an interview process. "In an interview people can put up a good front. And a questionnaire cannot take a dislike to you - it is a fairer way of doing it."

Ms Louisa Vincent, a recruitment consultant with the Achievers Group, says: "We do occasionally get people who try to be somebody they think the company wants them to be in the tests, but in general the tests are 85 to 90 per cent accurate."

HRM managing director, Mr Michael O'Leary, says "in no circumstances should a decision be made solely on the basis of a personality test. The only purpose of the test is to raise questions which can be addressed in an interview later."

He said that the tests are used to identify the strengths and weaknesses of people and to see what kind of role would suit them best in a company. However, Mr Steve Greenwood, managing director of Berkeley Recruitment, said the tests were especially important for sales and marketing companies in which a big part of the decision on whether to employ somebody will depend on their personality.

"For one direct selling client of ours, the results of personality testing is as important a part of his decision as the interview but another said he thought it was no more than pop-psychology."

Mr Greenwood believes there is a place for such tests in the selection process in that the results can confirm or dispel particular worries. But they are not the biggest part of the equation.

"The danger is that with an increasing number of companies using the tests, a candidate may have done a few tests, and this would make it inaccurate. The tests are not watertight but they are 60-70 per cent accurate."

A wide range of different personality tests are available and companies are using them at many different career stages - from basic entry level to appointments to middle level or senior management positions.

AIB Group use them as a developmental tool for people progressing through the management structure. They are used to identify weaknesses of managers and to address them through training courses.

Oracle's recruitment manager, Mr Seamus Brennan, said the group used a 10-minute test to get a description of a candidate's personality in four areas: dominance, extroversion, patience with tasks and conformity. "We then sit down with the candidate and go through the results with them."

Tests vary in length from 10 minutes to two and a half hours. They range from choosing options from a number of different feelings to concentrating on more specific job related issues such as team work.

A common theme in most of the tests is a fail safe mechanism or selection of truth questions spread through the examination to judge whether the candidate is masking his or her replies to give what they think are the right answers.

However, most admit that there is no guarantee that if a person is familiar with such tests and clever enough to lie consistently and identify the truth questions in questionnaires, employers and recruiters can be deceived.

Mr John McCullough, head of executive search and selection for Andersen Consulting, says: "There is always a risk that it will happen but we employ four to five licensed specialists who are trained to pick up on these things."

In any event, the days of the interview look to be far from over.