To ensure content validity, items selected for the constructs, shown in Appendix, were primarily revised from prior studies for the context of on-line shopping. All the constructs, except for the demographic variables of the subjects, were measured on a five point Likert - type scale. (Table 1) summarizes the operational definition, variable type, source of measurement items, and number of items of the three constructs in this study, including past on-line
shopping experience, perceived information overload, and subjective state towards buying decision.
On-line shopping experience was measured by the subjects' shopping frequency in e-store (form "never" to "more than 1 O times"). Some studies tried to incorporate the concept of "perception" to study information overload phenomena (Buchanan et al., 2000; Grise and Gallupe, 2000). Their definitions and measurements,
however, are not suitable for consumer buying context.