Personality tests give employers a profile of your interests, motivations and working style. Unlike aptitude tests there are no right or wrong answers, so you can’t really prepare for them. Employers use the results to identify characteristics that fit with the job role, rather than look out for one ideal personality type.
Personality questionnaires can explore the way you tend to react to different situations. If the test reveals that you prefer working on your own rather than working in a team for example, the employer may well ask you additional questions about team work during the interview.
Although it might be tempting, ‘faking’ answers is not a good idea. Answer honestly, as often different questions will be used to look for the same characteristic – so you are likely to be caught out if you choose answers you think they might be looking for. Also, you can never really be sure of what they are looking for and often they will want a variety of personality types (a team full of ‘leader’ types is probably not a good idea).
The questionnaires are usually not timed, but it is recommended that you choose your first reaction to the questions rather than spend time pondering their meaning.
Rather than personality questionnaires, employers usually give more importance to interviews and assessment centre tasks such as written exercises or presentations. So use your time to prepare for these elements of the selection process instead.