There are several common models for curriculum development that differ in their perspectives and approaches. The Tyler model is a linear, technical-scientific model that follows four basic steps: setting objectives, selecting content, organizing learning experiences, and evaluating outcomes. The Taba model is similar but emphasizes grassroots involvement of teachers. The Wheeler model depicts curriculum development as cyclical rather than linear. Walker's deliberative model describes how curriculum is naturally developed through platform-building, deliberation of alternatives, and consensus-based design.