Involvement theory derived from social judgment theory has raised great research interests for leisure scholars since 1990s. The study issues for leisure involvement range from its conceptualization, measurement, antecedent and consequence factors, building causal relations, testing variations of leisure involvement among different recreation activities, and management and marketing applications. Although several inconclusive arguments exist, leisure involvement theory provides solid bases to explain leisure participation behavior, especially in the cases of participation patterns, message processing, and decision-making patterns.

The primary purpose of this study is to examine the appropriateness of applying involvement theory on international tour type choices. Ex post Facto experiment design is used. In the research design, "travelers selected package tours" are defined as low/median involvement group and "travelers selected DIY tours" as high involvement group. Study results show involvement theory can be employed to analyze and explain travel purchase behavior successfully. First, travelling abroad decision belongs to median/high involvement. In terms of overall involvement degree, DIY tour travelers is significantly higher than package tour travelers. Secondly, the level of involvement has great influences on travelers' information searching behavior, travel decision making factors, and decision making processes. Third, based on Kapfer and Laurent's CIP model, this study successfully structured tourist involvement scale under five constructs, "importance", "rewards", "sign", "risk importance" and, "risk probability". Finally, five constructs independently and effectively measure the tourist involvement. However, various constructs function differently. "Importance", "rewards", and "sign value" constructs generally show apparent influences on tour purchase decision patterns. Comparatively, the impacts of "risk importance" and "risk probability" are not consistent.