This module reading explores the implications of different business models on organization design. After discussing the distinction between units focused on work processes and those devoted to markets, the analysis provides insight as to when to organize businesses by function, geography, products, customers, or expert knowledge. The analysis highlights the difference between operating core units designed for efficiency and market-facing units designed for responsiveness. Span of control and span of accountability are introduced as key concepts to direct organizational attention and ensure the effective execution of strategy. While this module is designed to be used alone, it is part of the Strategy Execution series. Taken together, the series forms a complete course that teaches the latest techniques for using performance measurement and control systems to implement strategy. Modules 1 - 4 set out the foundations for strategy implementation. Modules 5 - 10 teach quantitative tools for performance measurement and control. Modules 11 - 15 illustrate the use of these techniques by managers to achieve profit goals and strategies. View the full Strategy Execution series at: hbsp.harvard.edu/strategy-execution.