**7. Conclusion**

In recent years, there has been an explosion of literature on the external sourcing of innovation, particularly under the auspices of open innovation. Collectively, our results provide a view of what West et al. [13] described as the "when" and "how often" of innovation; providing (to the best of our knowledge) the first detailed, representative data of the internal and external innovation done by firms across three continents.

Using a new, representative survey of firms in seven industries in eight countries, we show that there has been pervasive recent adoption of external innovation sources such as universities, third-party experts, startups, and crowd. Despite this, internal sources remain the most important innovation sources for firms in three ways. They are most important for overall firm innovation, for producing the most-successful innovation projects, and for delivering competitive advantage. Why, then, are firms turning to external innovation sources? Our results suggest that it is because digital technologies have become so important and because firms lack the digital capabilities to innovate competitively in these areas.
