3.2. Measurement of audit committee monitoring
We consider three factors when measuring the strength of the audit committee:
(i) the independence of the audit committee from management,
(ii) the level of financial expertise of the audit committee members, and
(iii) the stock ownership of the audit committee members. We consider these factors as find that companies with an audit committee composed entirely of independent directors and having at least one member with financial expertise tend to pay higher audit fees. In addition, audit committee effectiveness has been associated with audit committee members' equity holdings
Measuring the quality of monitoring systems is difficult since different mechanisms can act as substitutes (Duellman et al., 2013). Thus, we use a broad definition of a strong audit committee to capture multiple aspects of monitoring. Our measure of audit committee strength, Strong AC, is a dichotomous variable equal to one (zero) if the company meets all three (two or less) of the following criteria: (i) the audit committee is comprised solely of independent non-affiliated directors, (ii) the audit committee contains at least one financial expert as defined by SOX, 6and (iii) the percentage of shares held by the audit committee members is higher than the median value of the sample. 7
The use of an index to measure audit committee strength is common in the literature but does have drawbacks. For example, the generation of an index is largely arbitrary due to the lack of an agreed upon theory to guide the construction (Brown et al., 2011). Furthermore, partitioning on a specific governance dimension might result in an indicator variable correlated with the specific governance variable, which could indirectly drive results. Thus, the use of an index to assess audit committee strength is a limitation of our study.