Recommender systems increasingly use contextual and demographical data as a basis for recommendations.
Users, however, often feel uncomfortable providing such information. In a privacy-minded design of
recommenders, users are free to decide for themselves what data they want to disclose about themselves.
But this decision is often complex and burdensome, because the consequences of disclosing personal informa-tion are uncertain or even unknown. Although a number of researchers have tried to analyze and facilitate
such information disclosure decisions, their research results are fragmented, and they often do not hold up
well across studies. This article describes a unified approach to privacy decision research that describes the
cognitive processes involved in users’ “privacy calculus” in terms of system-related perceptions and
experiences that act as mediating factors to information disclosure. The approach is applied in an online
experiment with 493 participants using a mock-up of a context-aware recommender system. Analyzing
the results with a structural linear model, we demonstrate that personal privacy concerns and disclosure
justification messages affect the perception of and experience with a system, which in turn drive information
disclosure decisions. Overall, disclosure justification messages do not increase disclosure. Although they are
perceived to be valuable, they decrease users’ trust and satisfaction. Another result is that manipulating
the order of the requests increases the disclosure of items requested early but decreases the disclosure of
items requested later.