When it comes to research in any field, there are several factors to be considered when it comes to how seriously it is to be taken, for example, the methodology used and its reliability. If research is conducted through a faulty methodology, its results should automatically be taken with a grain of salt.
The reliability of research is closely related to the methodology used for it. This is because the reliability means whether or not you will get the same results or answer when you use an instrument to measure something more than once. You can also say that reliability speaks about which research method is the one the produces more consistent and stable results.
A measure is said to be reliable if it’s applied to the object of study any number of times and it produces the same results. It’s important to remember that all research procedures involve a certain degree of error. This amount of error is what really can indicate the reliability of measurement; they are inversely proportional.
The lower the amount of error is the higher the reliability of the measurement, and vice versa. One way to solve this problem is by taking multiple measurements and then the scores were averaged. This can help in the consistency or stability of research.
In these terms, the reliability of research can be divided into four different categories:
Test-retest reliability
In this method, the reliability is tested by conducting the same test on more than one occasion over a period of time where the same sample group participates.
For example, the employees at a certain company are to fill out the same questionnaire about their satisfaction at work twice with an interval of one week. In this case, the test scores are compared to assess their stability.
Parallel forms reliability
In this case, the reliability of research is verified when the phenomena that are being studied are assessed through one sample group, but by using more than one assessment method.
For example, the company that is studying the level of satisfaction among their workers may use questionnaires, focus groups, and interviews and then compare the results for consistency.
Inter-rater reliability
With this method for testing the reliability of research or study, the results are obtained by different assessors while using the same methods. This reduces any subjectivity in the studies and increases the credibility of the results.
For instance, the company that wants to know how happy their employees are to be working there, so an observation method can be used through two unrelated assessors, so the inter-rater reliability relates to the differences between these two assessments.
Internal consistency reliability
This form of assessing the reliability of research is applied when you want to see how different the results are within the subjects of study that explore the same construct and then produce the same results. It can be represented in two ways:
- Average inter-item correlation, where a specific form of internal consistency that is obtained by applying the same construct on each item of the test.
- Split-half reliability has the subjects of a test to be split in half.