Understand The Differences Between Validity And Reliability

To answer this question, we should understand what is reliability and validity first. According to David S. (2010), objectivity and credibility are the technical terms that reliability and validity of the research refer to. Polgar, S. and Thomas, S.A. stated that accuracy of the test procedure is what validity concerned with. They also pointed out that reliability is the characteristic of reproducibility and consistency of the results of a measurement step. There are different types of test validity and reliability, for example, content validity, predictive validity, test-retest reliability and inter-observer reliability. For the test-retest reliability, the reliability of a research can be tested by managing the same procedure of measurement again to the same participants (Polgar, S. and Thomas, S.A., 2013). These two results should be correlated to each other. For instance, the identical observer rates the identical patients twice in order to test the consistency and …show more content…
Myrtveit, I. & Stensrud, E. (2012) also believed that a set of computation can be reliable but not necessarily being valid. This is because a researcher may keep the same results when he repeated the same set of measurement. An example of this is weighting a birthday cake on a weighting scale. If one put the birthday cake on the weighting scale and a 1kg result is obtained and then he put the same birthday cake back on the same scale, the result obtained is still the same. This reading is definitely reliable but obviously there are some errors. These errors may be derived from the calibration procedure of the weighting scale. Researchers should keep in mind that even a tool for measurement is involved it does not mean that the results are equal to the true valve. Thus, the observed value may not be true value and a scale can be reliable but