Mental Accounting Matters

Mental accounting is the set of cognitive operations used by individuals and households to organize, evaluate, and keep track of ®nancial activities. Making use of research on this topic over the past decade, this paper summarizes the current state of our knowledge about how people engage in mental accounting activities. Three components of mental accounting receive the most attention. This ®rst captures how outcomes are perceived and experienced, and how decisions are made and subsequently evaluated. The accounting system provides the inputs to be both ex ante and ex post cost±bene®t analyses. A second component of mental accounting involves the assignment of activities to speci®c accounts. Both the sources and uses of funds are labeled in real as well as in mental accounting systems. Expenditures are grouped into categories (housing, food, etc.) and spending is sometimes constrained by implicit or explicit budgets. The third component of mental accounting concerns the frequency with which accounts are evaluated and `choice bracketing'. Accounts can be balanced daily, weekly, yearly, and so on, and can be de®ned narrowly or broadly. Each of the components of mental accounting violates the economic principle of fungibility. As a result, mental accounting in ̄uences choice, that is, it matters. Copyright # 1999 John Wiley & Sons, Ltd.