There is no simple answer to this question. In this chapter, we will try to clarify some of the relevant issues, describe the strategies employed to increase the survey's validity and reliability, and speculate about the data's accuracy and limitations.
Reliability refers to the consistency or reproducibility of a measure.
If a measure is not reliable, it will not even agree with itself. For example, if students are administered a measure that has a low reliability on two consecutive days, it is likely that their responses would not be the same. Reliability is a necessary, but not sufficient precondition for validity. One way to increase the reliability and validity of a measure is to use a well-established measure that has demonstrated reliability and validity. Whenever possible, this was done in the TAP survey.