Final answer:
Auditors compare client data with industry data, client-determined expected results, and similar prior-period data to assess performance and identify trends.
Step-by-step explanation:
Auditors compare client data with all of the above options mentioned - industry data, client-determined expected results, and similar prior-period data. Auditors use industry data to compare a client's performance against industry benchmarks. They also compare client data with client-determined expected results, which are typically based on the client's own goals and targets. Additionally, auditors compare client data with similar prior-period data to identify trends and changes over time.