How would you measure the effectiveness of a training program designed to increase the accuracy of a company’s audits?

How would you measure the effectiveness of a training program designed to increase the accuracy of a company’s audits? How would you measure the effectiveness of a training program designed to improve loan processing in a financial services organization? What would be similar and what would be different about the two training programs?

HR question (there is no subcategory for it so I chose Operations Management.