Interpretation 101-3 of the AICPA Code of Professional Ethics provides four independence requirements for certified public accountants performing bookkeeping services. As such, these requirements are largely thought of as rules requiring compliance. The purpose of this study was to provide empirical evidence related to the question, "Can the guidelines in Interpretation 101-3 be effectively interpreted?" Accordingly, the research objectives were twofold: (1) to make an estimate of the effectiveness of independence discrimination resulting from the use of Interpretation 101-3 , and (2) to identify variables related to differences in CPAs' judgements of impairment and non-impairment of CPA independence in situations covered by Interpretation 101-3. The research methodology for this study was based on a case approach. Twelve situations developed from analysis of Interpretation 101-3 and discussions with practitioners were organized into twenty-four cases in which a CPA firm provided a variety of accounting services. These twenty-four cases were divided into two case sets of twelve cases each and then combined with two cases from a previous study by David Lavin. These cases were submitted to an expert panel for validation as to their relationship to Interpretation 101-3, and a predetermined "correct" judgement was established for use in analysis. A mail survey of the licensees of the Texas State Board of Public Accountancy was used for collecting data. The CPAs were provided with a copy of Interpretation 101-3 and asked to base their judgements exclusively on the standard. Hypothesis testing was used to determine the effectiveness of the independence discrimination resulting from the use of Interpretation 101-3. Statistical models were developed for evaluating differences in the effectiveness of independence discrimination and differences in the CPAs' judgements themselves.