Reliability and Validity
Reliability refers to the consistency of research results over time, while validity refers to the accuracy of the research in measuring what it is intended to measure. Both are essential for ensuring the quality and credibility of a study.
On this page:
- What is Reliability?
- What is Validity?
- How to Ensure Reliability and Validity
- When to Address Reliability and Validity
| Aspect | Reliability | Validity |
|---|---|---|
| Meaning | Consistency of results | Accuracy of measurement |
| Key question | Are results repeatable? | Are we measuring the right thing? |
| Focus | Stability | Correctness |
| Risk | Random error | Systematic error |
| Example | Same survey → same results | Survey measures actual concept |
Reliability vs Validity at a Glance
Reliability is about consistency, whereas validity is about correctness.
- Reliability → If you repeat the study, do you get similar results?
- Validity → Are you actually measuring what you intended to measure?
A study can be reliable but not valid — but it cannot be valid without being reliable.
What is Reliability?
Reliability refers to the extent to which the same answers can be obtained using the same instruments more than one time. In simple terms, if your research is associated with high levels of reliability, then other researchers need to be able to generate the same results, using the same research methods under similar conditions. It is noted that “reliability problems crop up in many forms.
Reliability is a concern every time a single observer is the source of data, because we have no certain guard against the impact of that observer’s subjectivity” (Babbie, 2010, p.158). According to Wilson (2010) reliability issues are most of the time closely associated with subjectivity and once a researcher adopts a subjective approach towards the study, then the level of reliability of the work is going to be compromised.
What is Validity?
Validity of research can be explained as an extent at which requirements of scientific research method have been followed during the process of generating research findings. Oliver (2010) considers validity to be a compulsory requirement for all types of studies. There are different forms of research validity and main ones are specified by Cohen et al (2007) as content validity, criterion-related validity, construct validity, internal validity, external validity, concurrent validity and face validity.
How to Ensure Reliability and Validity
Measures to ensure validity of a research include, but not limited to the following points:
a) Appropriate time scale for the study has to be selected;
b) Appropriate methodology has to be chosen, taking into account the characteristics of the study;
c) The most suitable sample method for the study has to be selected;
d) The respondents must not be pressured in any ways to select specific choices among the answer sets.
It is important to understand that although threats to research reliability and validity can never be totally eliminated, however researchers need to strive to minimize this threat as much as possible.
When to Address Reliability and Validity
Reliability and validity should be addressed primarily in the methodology chapter, but also considered throughout the research process.
You should:
- Explain how reliability and validity are ensured
- Link them to your research design and methods
- Acknowledge any limitations affecting them
- Demonstrate awareness of potential bias
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References
- Babbie, E. R. (2010) “The Practice of Social Research” Cengage Learning
- Cohen, L., Manion, L., Morrison, K, & Morrison, R.B. (2007) “Research methods in education” Routledge
- Oliver, V, 2010, 301 Smart Answers to Tough Business Etiquette Questions, Skyhorse Publishing, New York USA
- Wilson, J. (2010) “Essentials of Business Research: A Guide to Doing Your Research Project” SAGE Publications