In order to understand information system post-adoption phenomena, the expectation-confirmation model (ECM) was proposed. Past studies based on the ECM focus on a referent centered on the target IS being studied. The effect of this reference, captured through confirmation, has been strongly shown. However, the saliency of two additional reference effects, captured through self-image congruity and regret, has not been explored. In order to fill this knowledge gap, this paper attempts to develop a research model that extends the ECM by incorporating self-image congruity and regret as well as perceived enjoyment. For this extension, we synthesize the extant literature on continued IS use, self-image congruity, and regret. The analysis results tell us that self-image congruity plays a key role in forming two post-adoption beliefs, perceived usefulness and perceived enjoyment. It is also found that the absolute effect of regret on continuance intention is larger than those of other antecedents identified in IS. Overall, this study preliminarily confirms the saliency of self-image congruity and regret in post-adoption phenomena. Our study results is likely to help the IS community systematically address unexplored effects of self-image congruity and regret.
