Answer:
Interest expense is excluded from the Return on Net Operating Assets (RNOA) calculation as it is seen as a financing activity, not an operating activity. RNOA measures a company's operating assets' ability to generate profits without taking into account financing decisions like interest expense. This exclusion ensures a more accurate view of a company's ability to make profits from its core business. Additionally, this allows for better comparisons between companies with different financing structures or interest rates. In summary, RNOA is a valuable measure of a company's profitability from operating activities, and the exclusion of interest expense ensures that the measure reflects the company's core business performance.