Definition 3.9 Objective indicators objectively map empirical manifestations into symbolic ones, i.e., the mapping does not change from subject to subject. On the other hand, the mapping related to subjective indicators can change from subject to subject.
Since subjective indicators provide essential information on the behaviour and
perceptions of individuals, they are often used in many disciplines in the area of Social, Behavioural and Cognitive Sciences (Nunally and Bernstein 1994; Arrow 1963). Most subjective indicators are expressed in the form of ordered scale categories (e.g., a five-level ordinal scale for evaluating the degree of customer satisfaction from a product: 1-very dissatisfied, 2-dissatisfied, 3-neutral, 4-satisfied, 5-very satisfied).