“…What differs across the studies is the way income was measured, as well as the explicit reference to household, visiting party, average per family members (total or only adult), household head, or only the respondent. A group of scholars used gross income before tax (Asgary et al, 1997;Crouch et al, 2007;Davila et al, 1999;Jang and Ham, 2009;Kim et al, 2011;Leones et al, 1998). A second set of papers considered net income after tax (Alegre et al, 2009(Alegre et al, , 2010Dardis et al, 1981;Hong et al, 1999;Hong et al, 2005;Jang et al, 2007;Zheng and Zang, 2011).…”