Which of the following is least likely to be a research project by the Public Company Accounting Oversight Board (PCAOB)?

The least likely research project by the Public Company Accounting Oversight Board (PCAOB) is the compensation reporting model. The PCAOB's primary focus is on overseeing the audits of public companies and ensuring the accuracy and fairness of financial reporting. Their main objectives include improving audit quality, promoting auditor independence, and establishing robust auditing standards.

The compensation reporting model typically pertains to how companies disclose executive and director compensation in their financial statements, which falls under the broader realm of corporate governance and reporting rather than audit-specific standards and practices that the PCAOB primarily governs.

In contrast, auditor independence is directly relevant to the PCAOB's mission, as maintaining independence is critical for the integrity and objectivity of audits. Financial statement auditing standards are also core to the PCAOB's framework, as these standards dictate how audits are conducted. Lastly, investor protection methodologies align with the PCAOB's goal of ensuring that investors have confidence in the financial reporting and auditing processes of public companies. Thus, the compensation reporting model does not directly relate to the PCAOB's primary responsibilities, making it the least likely area of research for them.