Random error (e.g., caused by the order of items in the questionnaire or respondent fatigue) (Heeler & Ray, 1972).

Systematic error, such as method variance (e.g., variance attributable to the measurement method rather than the construct of interest) (Bagozzi et al., 1991).

Construct validity is used to determine how well a set of measurement items measure what they are supposed to measure. In other words, is the test constructed in a way that it successfully tests what it claims to test?  

The main objective of construct validity assessment is to reduce the effect of measurement errors in a data-set.