“…Because the absolute amount of debt is cumulative (Norvilitis et al, 2006;Stone & Maury, 2006), it cannot represent the level, intensity, or severity of debt. Although the majority of research used the amount of outstanding balance (amount of debt) as the dependent variable (Davies & Lea, 1995;Grieb et al, 2001;Livingston & Lunt, 1992, Norvilitis et al, 2006Pinto & Mansfield, 2006;Zhu & Meeks, 1994), some sensitive researchers have recognized this problem and then used the debt-to-income ratio (DeVaney & Lytton, 1995;Norvilitis et al, 2003;Stone & Maury, 2006;Tokunaga, 1993). Since it is difficult to define income for some special groups such as students or freelancers, some constructive research has been done using payment behavior to measure debt (Bowers, 1979;DeVaney & Lytton, 1995;Robb & Sharpe, 2009).…”