Design thinking is a human-centered problem-solving methodology structured around an iterative five-stage loop of empathize, define, ideate, prototype, and test. It was popularized by IDEO (David Kelley, 1991) and the Stanford d.school (2005), and is applied to product, service, organizational, and policy problems well beyond traditional product design. It is one of the most influential methodologies in modern innovation work and also one of the most-critiqued, with serious questions raised about whether the workshop-heavy version delivers durable outcomes.
The five stages, as taught at the d.school: empathize (deep customer research, often ethnographic, to understand the human at the center of the problem), define (synthesi...