Rob Williams Assessment Ltd have considerable experience in assessing the validity of psychometric tests. This is a one of the key final stages in any psychometric test design. In addition to test the SJT reliability and to advise on suitable cut-off scores which minimise any adverse impact (due to gender, age, ethnic group and disability).

Many of the UK’s and US’s leading test publishers have used Rob Williams Assessment’s to assist with ensuring the psychometric properties of their trial psychometric tests. We consult on how to improve any test’s psychometric properties, particularly the test’s internal reliability and construct validity.

Rob Williams Assessment Ltd are assessment specialist in both work and education settings.

Rob WilliamsAsk ROB (expert test developer) your questions by emailing

An Associate Fellow of the British Psychological Society, Rob Williams is a Chartered Psychologist with over 25 years of experience working and designing tests. He is also the author of five psychometric test design books and has worked for the leading global psychometric test publishers including SHL, Kenexa IBM, MBTI, CAPP and SOVA Assessment.

Personality test trends

Candidates may also have to take a personality test as part of the recruitment process. There is a vast array of personality tests, which pose questions about a candidate’s behaviour and personal preferences. A typical question may ask whether you prefer attending parties or staying home with a good book. These personality tests help employers to determine whether a candidate has the right profile for the role.

Some benefits of Personality Assessments

Firstly, there are many different applications of personality assessment results.

In counselling or coaching applications, an individual’s personality profile’ is most useful relative to their own person.

Whereas in clinical and occupational settings, their personality results have more application relative to other people (who’ve taken the same personality assessment)

Often, in our opinion personality assessment reports provide ‘unique’ insights when modelled on specific behavioural preferences, such as:

  • Firstly, when working under pressure.
  • Secondly, for digital leadership recruitment.
  • Thirdly, working in a team.
  • And then for specific careers.
  • Finally, when onboading.

The personality profile and other outputs are then used by the business to predict the candidate’s response to a wide range of work-related activities and hence, help to measure the suitability of that individual to a role within the company.

In summary. personality assessment data – especially when based on our personality trait test designs or personality type designs – provides incremental validity over other forms of assessment such as ability tests or interviews.

Biodata questions

Personality biodata questions measure a variety of constructs, including attitudes, personality attributes, interests, skills/abilities, past events and experiences. An individual’s learning history is of particular interest.

Which personality traits do employers look for?

Sackett and Walmsley used a well-established model for measuring personality known as the Big Five as the theoretical basis for their study. In the Big Five model, an individual’s personality can be described using measures of five personality traits: conscientiousness, agreeableness, emotional stability, extraversion, and openness to experience.

The researchers analyzed a large set of data on job interviews to find out which personality traits companies look for when they’re hiring. Much of the data came from an analysis of structured job interviews, in which employers assess candidates for particular personality traits in order to make sure they’re a good fit for the job and overall work environment. For example, a company that is hiring a salesperson would want to assess job candidates for the traits of extraversion and friendliness to make sure they’re likely to work well with customers.

After crunching the numbers, Sackett and Walmsley found that conscientiousness was by far the most highly sought after personality attribute for job applicants. Agreeableness–being cooperative, flexible and tolerant–was the second most prized person

Our Personality type career guidance

Your personality type certainly affects the way you think and act. Plus, other people’s perceptions of you.

Career success requires finding a job that matches your personality traits. The idea becomes doubly true once you start moving up the ladder. This is why you can guess what department somebody is from just by their attitude toward the company.  So before you accept a personality-type based promotion, you need to know what jobs you can and can’t do.

3) Focus groups

Thirdly, semi-structured focus group format represented the most suitable job analysis technique to use.

4) Role survey

Fourthly, a role survey based on the bank’s competency framework, with two questions per competency. Survey results informed the item writing process. The final 5-10 minute survey had two banks of questions with the stems:

  • How important do you do each of the following on a daily basis?
  • How important are the following to your job?

> > > Personality test design < < <

Candidate Experience Briefing

A separate briefing detailed the client style and language (US English) needs, including:

  • Reflecting the company brand
  • Engaging job applicants
  • Providing some elements of a realistic job preview
  • Overall look and feel to be consistent

Focus Group Briefing

  • Firstly, focuses on how best to structure the upcoming focus group sessions.
  • Secondly, a consideration of the outputs required.
  • Thirdly, how individual consultants could best run their focus group sessions.

The focus group aims were to confirm the

  • Role profile interview data.
  • Engender key stakeholder support .
  • To complete a few final visionary interviews.

Our Personality Test Process

We will work with you on any work personality test designs, including validation projects. Or to design the most suitable work styles tool to suit your needs.

Our Bespoke work Personality assessment designs process:

  • Reflect the personality, attitudinal and motivational aspects of the role-specific dimensions.
  • Leverage face valid personality tool questions.
  • Are capable of completion in 20 minutes approx.
  • Use a single-stimulus question format, called a Likert scale.
  • Adopt a normative format of scoring utilising a sten look-up table for each personality scale.
  • Use a Social Desirability scale to deal with the issue of faking or extreme scoring patterns.

2 Key Statistics – Work Personality Assessment Designs

1) Reliability of personality test design

There are many ways to statistically measure the internal reliability of each scale on a personality questionnaire. Probably the most common is Chronbach Alpha. The advantage of using this measure of a personality test’s internal reliability is the agreement in the literature of what represents an acceptable Chronbach’s Alpha score for any personality questionnaire scale. A score above .7 indicates an internally reliable scale.

Work Personality Test Designs

2) Validity of personality test design

  • Firstly, Predictive validity.
  • Secondly, Discriminate validity.
  • Thirdly, Content validity.
  • And then next, Face validity.
  • Plus finally, Construct validity.

Content Validity

  • How well the personality test samples relevant aspects of the psychological functions; as extroversion is made of being socially bold, eccentric, sociable, and lively.
  • A test measuring extroversion should use items that reflect all of these components.
  • The content validity cannot be assessed numerically.

Face Validity

  • In our opinion, most bespoke personality test designs are founded on a realistic model.

  • A solid foundation model then allows key psychological concepts to be translated into test items.
  • The extent to which the test items actually measure the psychological concept, is known as construct validity.
  • This construct validity is assessed indirectly by correlating the test scores to another test score. Of course, this second personality test is already known to measure the same psychological concept.

  • The construct validity of a new test measuring dominance might be assessed by correlating it to two dominance scales. These could be taken from the 16PF and EPPS personality tests.

    Predictive validity of bespoke work personality test

    • Predictive validity is an indication of how well the test score predicts future behaviour.
    • For example, test used for employment selection are expected to correlate with job performance.

    bespoke personality test design

    What is validity?

    “Convergent” or “construct” validity scientifically checks whether we’re really measuring what we’ve set out to measure.

    • In the case of pre-hire assessments, are we really measuring personality?
    • Are we identifying something else about our test-takers — their reading ability, English fluency, memory, or ability to stick with a task?
    • Are we left with actual personality data, or just a dataset of people who could finish a lengthy questionnaire?

    Personality Test Validation Stages

    Validation Stage 1

    • Who should complete the personality. Each participant should be doing a similar role. A sample in excess of 40-50 is required.
    • What job performance measures should be used and are available from HR. Examples of suitable job performance criteria:
    • sales figures
    • appraisal ratings
    • development or assessment center competency ratings or pass/fail criteria
    • length of service

    Personality Test Validation Stage 2

    An excellent way of obtaining job performance data is to use a managerial Performance Rating form. Managers rate behavioural criteria that are important in their particular role.  Some of the benefits include getting better quality data, getting around the “political” problems of appraisal ratings and covering all aspects of job performance focusing on those which would be more likely to correlate to the 16PF.

    At the same time it is worthwhile asking people to rate themselves on the same criteria using a Performance Rating form.

    Final Stage of Personality Test Validation

    ROB WILLIAMS ASSESSMENT will conduct all the statistics – requiring a couple of days work – and share the results with the client in the form of a short report – also requiring a couple of days work.


    One of the commonest criticisms of personality tests has been their fakeability. All personality assessment output relates to the candidate’s own answers and any pertinent points can be discussed at interview.

    Test developers can build-in strategies to make faking more difficult, such as using different types of social desirability scale. Giving a consistently false picture is more difficult with a robust personality questionnaire. It also assumes that the candidate knows enough about the interviewer and their prospective employer to be able to guess at the ‘correct’ personality profile. A lengthy completion time may also indicate that a candidate has crafted their answers around what they consider to be a ‘correct’ personality profile.

    Work Personality Test Designs


    The MBTI® personality type instrument indicates an individual’s preferred behavioral styles. In particualr for interacting, using information and making decisions. It does not provide any indication of ability or suitability for a role. People of all types can do anything. However their natural tendency or first instinct may be to act in a certain manner.

    There is research to suggest that people of certain types may find some professions more attractive. However there is no research to suggest that they will perform better than people of other types.

    Our other psychometric test design specialities

  • Firstly, here are some examples of our specialist situational judgment test designs.
  • Secondly, our values situational and competency values-based assessment designs.
  • We also specialise in aptitude test design projects.
  • Then next our customised leadership assessment projects and pre-employment sift designs.
  • Plus, our emotional intelligence assessment designs. and high potential test designs.
  • And then next, our top bespoke personality test design projects and our school aptitude test designs.
  • Finally, some examples of the bespoke psychometric tests designed recently for clients.

– – Personality Test Design – –