George Roberts, and Cathy Zee are on an audit engagement for Loewen Windows Ltd. 

During planning, George has decided to use benchmarking as an analytical procedure. The engagement partner agreed with George's approach but cautioned him that he needed information sources that would ensure the reliability of the data for his benchmarking procedures. 

Cathy has been assigned to the audit of Accounts receivable and Sales. She has decided to use a substantive approach, and she is trying to determine to whom she should report weaknesses in the client's internal controls.

Assist George: What information sources are generally considered to be reliable when conducting benchmarking exercises?

Assist Cathy: What would she need to document for the audit approach? What can she  about weaknesses in a client's system of internal controls?