Recombinant uncertainty in technological search

While the Course of technological change is widely accepted to be highly un certain and unpredictable, little work has identified or studied the ultima te sources and causes of that uncertainty. This paper proposes that purely technological uncertainty derives from inventors' search processes with unf amiliar components and component combinations. Experimentation with new com ponents and new combinations leads to Less useful inventions on average, bu t it also implies an increase in the variability that can result in both fa ilure and breakthrough. Negative binomial count and dispersion models with patent citation data demonstrate that new combinations are indeed more vari able. Ln contrast to predictions, however, the reuse of components has a no nmonotonic and eventually positive effect on variability.