Validating Instrument Quality for Measuring Students´ Acceptance of an Online Discussion Site (ODS)

The primary purpose of this study was to provide validity evidence for the items used to measure the intention to use an Online Discussion Site (ODS). Seventy seven students participated in this study. The extended Technology Acceptance Model (TAM) model was adapted for this study. With the use of the Rasch analysis, the item validity in extended TAM model was evaluated. There are a few aspects of validity in relation to the Rasch analysis. This paper discusses validity in terms of item quality. To maximize the quality of items in the model, the item removal process was conducted. There were two criteria used to identify the quality of items, (1) point measure correlation and (2) fit statistics. Items that did not meet these two criteria were eliminated. There were 24 items in the original model but results show that only 23 items can be used for modelling students´ intention to use the ODS.