Measure            ----------------------->           CONSTRUCT    

       Our self-report         ----------------------->            Academic Intrinsic

           Question                                                              motivation

                    X =  T  +  Es  + Eu

               X = a given test score

               T = true score

               Es  =  systematic error

               Eu  = unsystematic measurement error

Our Measure = the construct of interest + other constructs +random error

a person's score =  academic motivation + social desirability? +  carelessness?

    on our question                                        academic ability?      misinterpretation?

                                                                             etc.                    imprecision in

                                                                                                      measurement