(5) Balance of the four functions
It is difficult to develop an evaluation method that satisfies all four functions. Particularly in VT where mostly skills are measured, adequacy and objectivity/reliability are in a trade-off relationship.
For example, when evaluating the attainment of a target objective, “capable of xx,” concerning a certain skill, a
multiple choice test on the work sequence may have very high objectivity but its adequacy is extremely low. On the other hand, when implementing a practical skill test to improve adequacy, objectivity could become low depending on the evaluation method.