Final answer:
Management accountants use Cost-Volume-Profit analysis to guide strategic and operational decision-making, focusing on how cost changes and volume impact financial metrics and profitability.
Step-by-step explanation:
A guideline used by management accountants to assist in strategic and operational decision-making is Cost-Volume-Profit analysis (C). This technique allows businesses to understand how changes in costs and volume affect a company's operating income and net income. It involves the calculation of various financial metrics, including accounting profit, which is the total revenues minus explicit costs - including depreciation, average profit or profit margin, average total cost, and average variable cost. Understanding these concepts is crucial for decision-making within a firm as they directly influence pricing, budgeting, and strategic planning.
Other concepts like constant returns to scale, diminishing marginal productivity, diseconomies of scale, economic profit, and economies of scale are also significant in cost accounting and management accounting. These concepts help in understanding the impact of scale on costs and, thereby, on profitability. However, these are not the primary guidelines for decision-making as indicated in the original question, but they provide additional context for understanding financial performance.