validity and reliability of research instrument example

Below is a visual representation of validity, again using a dart board. The measuring tape may consistently say that a woman is 12 inches tall, but that probably is not a valid measure of her height. However, an instrument may be reliable but not valid: it may consistently give the same score, but the score might not reflect a person's actual score on the variable. For an instrument to be valid, it must consistently give the same score. An instrument must be reliable in order to be valid. There is a link between reliability and validity. Just like research studies must be evaluated for the quality of the conclusions drawn by critically examining the methodologies such as the sample, instruments, procedures, and data analysis, so too does the validity evidence need to be evaluated to determine whether the evidence does in fact support that the instrument measures what it claims to measure.

Just because an instrument is face valid does not mean it is construct valid, and just because an instrument is valid in a sample of American youths does not mean that the instrument will be valid in a sample of Nigerian youths. Instead, validation is a process of gathering and evaluating validity evidence. It is important to understand that an instrument is not declared valid after one piece of validity evidence. Does the instrument in fact measure mathematics skills, or does it measure something else, perhaps reading ability or the ability to follow directions? For example, an instrument was developed to measure mathematics skills. This step examines the validity of an instrument, or how well the instrument measures what it is supposed to measure. The last step examined the reliability, or consistency, of the instrument. Educational Psychology Conducting Educational Research

Validity and reliability of research instrument example