importance of validity and reliability in research

In the case of social research, unreliability in the questionnaire as a measuring instrument might arise in the measurement of any concept due to such things as a question or answer categories being so ambiguous that the respondent is unsure how he or she should answer. If your weight remains constant at 60 kilograms, but repeated measurements on your bathroom scale show your weight to fluctuate, the lack of reliability may be due to a weak spring inside the scale.

How can a measuring instrument be unreliable?

However, if the object being measured does change in value, the reliability measure will indicate that change. Reliable instruments are robust they work well at different times under different conditions. The essential conditions in such a measurement process are that repeated administration of the same instrument must be made under essentially similar conditions, and the object will not be changed over time. If the tailor takes repeated measures of the fabric and each time comes up with the same length, it is said that the tape measure is reliable. Put simply, reliability is the degree to which a measuring procedure produces similar, in other words, consistent outcomes when it is repeated under similar conditions.Ī tailor measuring fabric with a measuring tape obtains a value of the length of the fabric as 20 inches. We discuss these concepts in turn in the following sections. accurate (which refers to validity) is the information obtained?.how consistent or dependable (which refers to reliability), and.Social researchers primarily employ two criteria for evaluating the quality of their measures. Situational errors are ones that occur neither at random nor systematically but occur as a result of particular personal characteristics of the individual(s) or other special circumstances that can influence the measurement process.įatigue, for example, of the respondents or an unusual environmental detraction, may generate a situational error. Likewise, a defective weighing machine or any other defective measuring device is likely to produce a systematic error in the measuring process.

Importance of validity and reliability in research