Understanding Ability Test Results
Measuring Performance & Potential.
When candidates take an online ability test, their answers are compared to a group of people with a similar background who have taken the test in the past for example:
- Similar Education Level
- Job Level / Type
- Industry Sector
The particular comparison group is called the ‘Norm Group’ or ‘Performance Norm Group’. The most appropriate norm group is selected depending on the sector and role, for example:
- Public Sector workers at Manager/ Professional Level.
- Customer Services / Supervisor Level.
- Administration and Support / Non-Managerial Level
The Norm Group used will be shown in the report as part of the performance measure.
Scores for each test are displayed graphically as a scale score - the higher the number, the better the score.
There are different types of Scale that are graphically displayed.
The three most common are:
- Sten scores (between 1 and 10)
- T-scores (between 1 and 100)
- Percentiles
Performance Measure | Sten Score
This graph shows that across the whole comparison group, test results are normally distributed. In other words, people will achieve a full range of scores, from very low to very high. Generally, most people will score within the mid-range rather than at the extremes. As a result, you get bunching of results around the middle of the graph. Therefore, for Sten scores, anything between 4 and 7 is considered within the average band.
Performance Measure as a Percentile
Test reports generally show Percentile scores as the main test result, however these are a little different.
A percentile score of 90 indicates that the candidate scored better than 90% of people in the total comparison group, so a very good score. Due to the bunching effect of the normal distribution, scores between 30 and 70 percentile are deemed to be within the average band – see this example. (The percentile score is different from a percentage score which is simply a way of showing how many questions were answered correctly.)
Work Rate
This is an indication of how many questions the candidate managed to get through in the time and can be expressed as a percentage, or fraction of the total e.g. 75% or 15/20.
Hit Rate
This is an indication of how many of the questions attempted the candidate got correct, again this may be expressed as a percentage or fraction e.g. 66% or 10/15.
Understanding Ability Test Results | Additional Things to Consider
Looking at Hit Rates and Work Rates in more detail.
Additional things to consider might be:–
- If the candidate had worked more slowly and got a lower work rate, would they have achieved a better hit rate and got more correct?
- It is also possible that candidates may have identical hit and work rates, but slightly different percentile scores. This is because of the way some tests are constructed. For Example: Item Response Theory.
Item Response Theory explained.
Tests using the Item Response Theory offer a random selection of questions from a ‘question bank’ of the appropriate level. You need to take into account that some of the questions might be slightly harder or easier than others. As a result, candidates may answer the same number of questions and get the same number correct. However, the difficulty of the questions may have been different and this is expressed in the final Percentile score achieved.
Further support for HR and Talent Development Teams when using Psychometric Assessments and Tests.
Ability Tests, along with the majority of psychometric tests can be taken online. However, occasionally your HR Team may require evidence the correct individual has completed them. For this purpose, verification questions are available for the interview. Further information on the use of Psychometric Testing within an occupational setting, for example; which ones to choose, can be found here: [READ MORE]
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