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    A Post-SOX Examination of Factors Associated with the Size...
    research summary posted October 31, 2013 by Jennifer M Mueller-Phillips, tagged 01.0 Standard Setting, 01.05 Impact of SOX, 05.0 Audit Team Composition, 05.04 Staff Hiring, Turnover and Morale, 13.0 Governance, 13.01 Board/Audit Committee Composition 
    A Post-SOX Examination of Factors Associated with the Size of Internal Audit Functions
    Practical Implications:

    This study provides insights that should be useful for CAEs and boards of directors (or audit committees) in discussions related to (1) internal audit philosophy regarding its potential contributions to an organization, (2) alternative staffing models, (3) resource allocation, and (4) embracement of audit technology. The study could also help guide external auditors’ evaluation of client internal audit functions. The authors find that the mission of internal audit functions differs from organization to organization. Additionally, the results suggest that internal audit functions used for leadership development purposes (i.e., a rotational staffing strategy) are larger, presumably because the staff have less experience and staff are rotating in and out of the department more frequently. Finally, these findings help illustrate the importance of internal audit proving that it is ‘‘value added’’ to the organization. Management and audit committees are often looking for more than financial statement compliance, and those internal audit functions that have responded to these greater needs are rewarded with more resources, likely because they are perceived to deliver more value.

    For more information on this study, please contact Karla Johnstone.


    Anderson, U. L., M. H. Christ, K. M. Johnstone, and L. E. Rittenberg. 2012. A Post-SOX Examination of Factors Associated with the Size of Internal Audit Functions. Accounting Horizons 26(2): 167-191

    Internal Audit; resource allocation; budgeting; staffing.
    Purpose of the Study:

    Internal auditing is a key element of an organization’s governance, risk management, and internal control structure. However, many organizations struggle to know if the investments they make in the internal audit function are appropriate and use size benchmarking data (e.g., firm assets, revenues, number of employees) to determine if internal audit is appropriately sized. However, benchmark data fails to incorporate other factors that influence internal audit size such as the effectiveness and efficiency of an internal audit function, the scope of the internal audit mission, or internal audit objectives and staffing strategies. Therefore, the objectives of the study include the following:

    • Develop and test a conceptual model that articulates the factors associated with internal audit size in the contemporary post-SOX era. The model includes four determinants of internal audit size: (1) audit committee characteristics, (2) internal audit characteristics and mission, (3) assurance activities performed by others (including internal audit outsourcing providers and assurance provided by other functions within the organization), and (4) organization characteristics.
    • Conduct an examination using contemporary post-SOX data in order to extend earlier related research on internal audit sizing by considering a variety of previously unexamined characteristics that differentiate internal audit functions from one another.
    • Examine the state of internal audit staffing in the post-SOX environment.
    Design/Method/ Approach:

    The authors collected data with which to test their model by first conducting field interviews with a variety of chief audit executives across a broad range of industries. The authors then distributed a survey to chief audit executives that are members of the Institute of Internal Auditors. The survey includes questions related to each of the four determinants of internal audit size (as mentioned above), as well as internal audit size based on number of internal audit personnel. The field interviews were conducted between August 2006 to November 2006 and the survey was conducted from August 2007 and October 2008.


    The authors find that internal audit size is positively associated with:

    Audit Committee Characteristics:

    • the size of the audit committee;
    • the frequency of audit committee meetings with the CAE
    • audit committee review and approval of the internal audit budget.

    Internal Audit Characteristics and Mission:

    • CAE tenure in the organization;
    • performance of IT auditing;
    • the use of a staffing model in which internal audit is used for rotational leadership development
    • the use of sophisticated audit technology.

    Organization Characteristics:

    • the total assets of the organization
    • the number of foreign subsidiaries that the organization possesses.

    Further, the authors find that internal audit size is inversely associated with:

    Internal Audit Characteristics and Mission:

    • the percent of audit staff designated as Certified Internal Auditors.

    Internal Audit Activities Performed by Others:

    • the extent of internal audit activities outsourced to a third party.
    Audit Team Composition, Governance, Standard Setting
    Board/Audit Committee Composition, Impact of SOX, Staff Hiring - Turnover & Morale