Why is construct validity said to be a difficult type of validity evidence to collect?

A) Statistical analyses to examine this type of validity are complex
B) The amount of items needed on the measure is very large
C) It is often obvious to the test taker what the measure is evaluating
D) Defining the construct and accurate measurement are difficult to achieve

Construct validity refers to the degree to which a measure actually measures the construct it is intended to measure. This requires a clear and accurate definition of the construct, as well as a method for accurately measuring it. These are difficult to achieve and can make it challenging to collect construct validity evidence. Statistical analyses and the number of items needed on the measure are important considerations, but they are not the primary reasons why construct validity evidence is difficult to collect. It may also not be obvious to the test taker what the measure is evaluating, as measures can be designed to minimize bias and increase objectivity.