Series of measurements are taken to make sure that the experiment is able to measure different sets of conditions under which the person or the instrument has to work.
Now the question arises how to make sure that the series of measurements are not only reliable but valid as well. Or can we make use of a measurement which happens to be reliable but low on reliability or vice-versa. This study cannot be an area specific but it cannot be generalized for all experiments as well. There might be some areas where we can use such measurements, but there might be areas where we need to be doubly sure that the measurement is both reliable as well valid. It is worthwhile here to mention that while validity can be tested and can be termed as an objective parameter, it is difficult to do exact calculation for reliability as it is subjective in nature. Reliability is therefore estimated in order to come to the nearest perfection point. Four general classes of reliability are1;
While there's no doubt that a measurement with high validity and high reliability is the most sought after type of measurement, a measurement with low validity and low reliability is never used for making any calculations. ...Show more