Validity and reliability are two important features of all tests including Psychometric tests. Validity is at the core of testing as it legitimizes content of tests which implies that information gathered from test results is relevant for the concerned topic. On the other hand, reliability defines how consistent a measure is of a specific element, over a period of time and between various test takers.
Validity - To label a test as valid it has to pass a series of measures.
- Concurrent validity: Implying that the test must stand up to previous analysis in the same subject. This relies on previously validated tests.
- Criterion validity: It measures how well content or qualities being tested may help predict uses in future of the same type; a personality test may predict certain behaviour, but it is valid only if behaviour manifests in real life.
- Content validity:This concept is used mostly in clinical psychology. This measures an evaluation of how well it covers the complete portion of personality or symptoms being tested for. It needs authorities to validate that this portion comprises of the whole picture of an illness.
- Predictive validity: It resembles criterion validity in that it deals with the predictive nature of a task/ question on a test; this kind is used mostly while comparing scores on a task related to work to how an employee is really scored on that task by employer.
- Construct validity: It is possibly the most crucial factor for psychometric testing and aims to review whether the test is really testing what it is meant for.
Why is it important?
It provides future employers a real idea of how applicants would perform on the job applied for. It ensures that the best persons are chosen for the jobs.
Reliability - It reveals how consistent the results of the tests are over a period of time as well as between various test takers. For instance, in a test measuring personality traits must yield the same results from a candidate no matter how many times the test is administered.
Reliability has certain sub-types:
- Reliability of Parallel forms: This is measured when there are two types of tests containing same elements but with various procedures or equipment. If results are the same, the tests are deemed as reliable.
- Reliability of Internal consistency: This considers items within a test. The internal reliability between items is evaluated. For example, a psychometric test like Psychometric Assessment may feature 2 or more questions asking the same thing and if test takers answer the same, the test is deemed reliable.
- Reliability for Inter-rater: This makes use of two individuals to rate or mark the scores of a psychometric test. If the scores are identical, the inter-rater reliability is confirmed.
- Reliability in Test- reset: This is the last subtype. It is garnered by giving the same test at two different times and providing the same results every time.
In most cases, there will be small discrepancies in complete reliability of a test because it is almost impossible to locate all defects. But reliability is an important part of psychometric tests as there is no use for a test which yields different results from the same person at different times. You can also create the profile and here you can find profile creation sites.