本研究探討會計師事務所提供之何種專業服務最能有效使用人力資源來創造收入。實證結果顯示，在給定的人力資源規模下，管理諮詢服務對事務所的收入貢獻最大。這種型態在沙賓法案對會計師事務所提供之管理諮詢服務加以限制之後，仍然存在。本研究並發現，在該法案實施後，因為加強對審計及內部控制評估的要求，會計師事務所員工具有會計師資格者成為事務所生產力的重要驅動因素。

This paper examines which type of professional services provided by accounting firms can most effectively utilize human resources in generating revenues. Results indicate that for a given level of human resources, management advisory services (MAS) contribute the most to an accounting firm’s revenues. This pattern continues to hold after the passage of the Sarbanes-Oxley Act (Act) despite the restriction on MAS imposed by the Act. In addition, with the increasing emphasis on auditing and certification of internal control services in the post-Act period, accounting firms’ employees with CPA designations become significant drivers of accounting firms’ productivity.