Age of Subjective Engineering - Emotional Engineering - page 5

Let us consider people who are good at sports, but may not be so good in other
! fields. If these people are encouraged in sports, they would become very good
athletes. So what is more important is to look at the examinee's latent trait and to try
to expand his or her capabilities to the full than to tell everybody to get good scores
without due consideration to their traits or abilities. People have different traits and
their ! fields of excellence vary from person to person. And their rooms for growth
vary from person to person.
People feel happier when they can expand their abilities to the maximum in their
own strong ! field. They will be ! filled with the feeling of ful ! llment when they
accomplish it. What IRT pursues is to ! find latent traits and expand them to the
maximum, rather than to force everybody to get the good score.
Thus, IRT focuses on traits or rooms for growth, not scores. But current dis-
cussions on diversi ! cation in engineering seem to focus on diversi ! cation of out-
comes. They do not care about their customer traits or their ranges of expectations.
What is more important in design and in marketing is to pay attention to individ-
uals' traits. How much they expect and how much room there is to respond to such
expectations (Fig. 1 ) .
Even if the level of expectation is low and room for upgrading is small, the
customer will feel very happy if his or her expectations are satis ! ed. This is much
greater than just selecting a product which seems to meet their needs among offered

Fig. 1 Classical test theory
and item response theory

Classical Test Theory

Item Response Theory