Validity is more critical to measurement than reliability because without validity, reliability is meaningless. For example, a bathroom scale may give a weight each time a person weighs themselves, which proves the scale is reliable in giving feedback. If the scale displays an incorrect weight each time then it is not a valid weight and a person cannot accurately measure themselves to know if a goal is being met or not. Validity and reliability can also be thought of in terms of a person and their work.
A person may show up to work on time and complete all tasks that are required everyday, which proves they are reliable, however if they tasks are not completed correctly then there is no Aladdin to work and it must be redone. Finally, validity can be proven through tests and procedures. B. Content validity is the most difficult type of validity to determine. Content validity refers to how well a test measures the items for a study for which it is intended.
For example, a math test to test basic level knowledge for college lacks content validity if the test only covers one aspect of math such as algebra. Content validity is the most difficult type of validity to determine because it is opinionated. One person who is an expert in a field may determine that certain questions are added to properly measure what is intended, whereas a different person who is an expert in the same field may determine different questions are needed to measure the same thing. C.
A valid measurement is reliable, but a reliable measurement may not be valid. I agree with this statement because a valid measurement can be proven through test criteria and a reliable measurement may be inaccurate because calculations may have been performed incorrectly or the tool or machine used to perform the measurement may not be properly calibrated, which would give a reading that is not valid. D. Stability and equivalence are essentially the same thing. Stability focuses on personal and situational changes over a period of time (Cooper and Schneider, 2014). Equivalence focuses on changes at a single point in time among observers and samples of an item” (Cooper and Schneider, 2014, p. 261). Stability and equivalence are not the same thing because stability is achieved when only one item or event is measured multiple times with the same results achieved. Equivalence is determined when two different items or events produce the same or similar results.