Entry for 'March 24, 2017'
A Nomological network is a representation of the concepts (constructs) of interest in a study, their observable manifestations, and the interrelationships among and between these. The term "Nomology" has been derived from the Greek, meaning "lawful", or in philosophy of science terms, "lawlike". It was Cronbach and Meehl's view of construct validity that in order to provide evidence that a measure has construct validity, a nomological network has to be developed for its measure.
The elements of a nomological network are:
Must have at least two constructs;
Theoretical propositions, specifying linkages between constructs: "As age increases, memory loss increases".
Correspondence rules, allowing a construct to be measured.
Operationalization: "Age" is measured by asking "how old are you?"
Empirical constructs or variables that can actually be measured. These are operationalized theoretical constructs.
Empirical linkages: Hypotheses before data collection. Empirical generalization after data collection.
Validity evidence based on nomological validity is a form of construct validity. It is the degree to which a construct behaves as it should within a system of related constructs (the nomological network).
Cronbach, L.J.; Meehl, P.E. (1955). "Construct validity in psychological tests". Psychological Bulletin. 52 (4): 281302. doi:10.1037/h0040957. PMID 13245896.