‘Crowding Out’ or ‘Crowding In’? How Idea Evaluation Affects Idea Generation Among Decision-Makers

Organizations rely on their employees to produce many high-quality ideas for the improvement

of products, processes, and strategies. Evaluators such as managers and technical experts

need to not only assess these ideas, but also face expectations to contribute ideas of their

own. We investigate this task duality by asking how idea evaluation activities affect evaluators’

ideation performance. While much of the creativity and innovation literature points to

a crowding-out effect, some theoretical arguments support idea crowding-in. Using data from

a multinational firm’s idea management system and a difference-in-differences framework, we

find robust evidence of substantial idea crowding-in: Evaluators’ likelihood of idea generation

increases by 205% on the day that they evaluate ideas, and remains elevated for the following

two weeks. Extensive analyses support knowledge recombination as the key mechanism: By

exposing evaluators to unfamiliar knowledge, idea evaluation creates new opportunities for recombination

and idea generation. The ideas that evaluators generate post-evaluation are 19%

more valuable (but not more novel) than those they generate outside the post-evaluation window.

We contribute to innovation scholarship by identifying a hitherto overlooked effect of idea

evaluation: triggering idea generation among evaluators.

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