“Important in identity theory because the salience we attach to our identities influences how much effort we put into each role and how well we perform in each role.” (Desrochers & Thompson)
“Identity salience is conceptualized (and operationalized) as the likelihood that the identity will be invoked in diverse situations” (p. 257). (Hogg, Terry, & White, 1995).
“Identity salience represents one of the ways, and a theoretically most important way, that the identities making up the self can be organized. Identities, that is, are conceived as being organized into a salience hierarchy. This hierarchical organization of identities is defined by the probabilities of each of the various identities within it being brought into play in a given situation. Alternatively, it is defined by the probabilities each of the identities have of being invoked across a variety of situations. The location of an identity in this hierarchy is, by definition, its salience” (p. 206, emphasis theirs) (Stryker & Serpe, 1982).

As defined by Andreassi, Desrochers & Thompson citing Burke & Reitzes in Identity Theory, A Sloan Work and Family Encyclopedia Entry. Retrieved from the Sloan Work and Family Research Network website:  Burke, P. J. & Reitzes, D. C. (1981). The link between identity and role performance. Social Psychology Quarterly, 44, 83-92. Hogg, M., Terry, D. & White, K. (1995). A tale of two theories: A critical comparison of identity theory with social identity theory. Social Psychology Quarterly, 58, 255-269. Stryker, S., & Serpe, (1982). Commitment, identity salience and role behavior: Theory and research example. In W. Ickes & E. S. Knowles (Eds.). Personality, Roles, and Social Behavior. New York: Springer-Verlag.