Experts have to use assessment instruments with great level of reliability. If there is a case in which an assessment instrument can be reliable but not valid, then there are some cases in which it cannot be reliable and eventually not be valid at all. As defined earlier, validity of a certain thing determines up to what level of reliability has to be given to it.

On the other hand, an assessment instrument that is not reliable can never be deemed valid. There has to be another external factor and in this case the level of reliability and validity of an assessment instrument may vary with respect to its user. In the above illustration, the entire issue is not a two-way process between the reliability and validity issues within the assessment instrument. Thus, a higher level of reliability cannot be given to the assessment instrument considering that the validity issue is in question. In this case, the reliability and validity of the assessment instrument is associated with its user. The assessment instrument therefore has to be used by the right person in order for its result to be valid and in general, it can be reliable. Thus, this is the same as the assessment instrument is not valid at all considering that it gives results but cannot be acceptable. However, the use of the assessment instrument cannot be entirely valid if the person using it is not an expert at understanding the results from the assessment. There are corresponding results in the assessment using the said instrument. Suppose for instance a person used an assessment instrument.

There are some cases in which an assessment instrument can be reliable but not be valid. It is in line with this that reliability and validity are strongly linked with each other through a certain level of acceptability and trust. Acceptability and trust are highly associated with the reality, what is seen or observed or measured, the information given and what the human logic could readily understand or perceive (Nooteboom, 2002 Damer, 2008 Carter, 2009).

Validity tells up to what extent a certain thing has reliability because it gives a picture of certain level of acceptability and trust. Validity on theother hand is a certain measure that would make something reliable. Reliability and validity Reliability refers to a value that can be given to something with certain level of acceptability and trust.

Reliability and validity psychology