Six experiments were conducted to determine whether idea checklists increased idea quantity and quality. College students were allowed 10 or 20 minutes or unlimited time to find ideas for product improvement problems. Results indicated that the only checklist which significantly stimulated productivity was composed of just seven general categories of solutions (e.g., change shape, change material). Another creative thinking technique, the morphological synthesis procedure (Allen, 1962), also significantly stimulated idea production, but a direct comparison with the brief checklist condition was not meaningful. Subjects provided with longer checklists, including Osborn's (1963) 73 idea spurring questions, performed no better than controls. With additional problem solving time, rate of idea generation decreased but idea quality increased. Object complexity, manipulated in two timed studies, was not systematically related to product improvement scores, and instructional constraints to be original and be practical decreased idea frequency. It was thus concluded that creative output can be increased by teaching deliberate techniques for generating new combinations of ideas. (Author/JD)