Big 4 firms use industry specialization as a quality signal (Ferguson et al. 2003) and it is
frequently used as a proxy for audit quality in empirical research (Craswell et al. 1995; Kwon 1996;
Hogan and Jeter 1999; Krishnan 2003; Carcello and Nagy 2004; Francis 2004; Lim and Tan 2008).
Archival research confirms the benefits of industry specialization across a variety of audit-quality
measures (i.e., higher earnings response coefficients, lower discretionary accruals, less fraudulent
reporting, and higher audit fees; see a summary of this literature in Francis [2004]).
Task expertise is gained through training and experience gained during an audit. Early
theoretical literature proposed the unique effect of task-specific experience on auditor performance
(Marchant 1990; Libby 1995), and behavioral research has confirmed this hypothesized link
(Bonner and Lewis 1990; Choo and Trotman 1991; Ashton 1991; Be´dard and Chi 1993; Tan and
Libby 1997; Wright 2001; Thibodeau 2003).