Final answer:
Marketing changes, operational changes, and staff changes influence a quick-serve restaurant's sales forecast and are considered internal changes, important for calculating menu costs.
Step-by-step explanation:
Marketing changes, operational changes, and staff changes affect a quick-serve restaurant's sales forecast and are categorized as internal changes. These elements are part of the internal dynamics that a business must manage. Changes such as optimizing the menu or any marketing strategy, operational adjustments for efficiency, and staff changes are all shifting components that can influence the sales forecast of a restaurant. In particular, staff changes can make a significant impact because they directly affect service quality and operational efficiency. It is crucial in quick-serve restaurants where speed and quality are paramount for customer satisfaction and retention. Overall, these internal changes directly correlate to the concept of menu costs, as described by modern Keynesian economists. Menu costs reflect the expenses related to changing prices and the associated operational changes, such as the adjustment in staff procedures or marketing efforts. When considering changes to prices or operations, these costs need to be balanced against the potential benefits, especially in a fast-paced quick-serve environment.