How effective product managers get things done and deliver results
Execution is about getting things done. A product manager is responsible for the end results of the product development process. In order to get results, the product manager must be able to get things done in the company, no matter the difficulty or organizational complexity that the task may require. Product managers who can execute are extremely useful to teams and companies because they are able to make the hypothesized results real.
Execution is not the simple act of following a plan. A plan will always be a poor version of reality. Theoretical plans, no matter how well-defined with excellent product thinking and communication, are ultimately still plans. They set the groundwork for where to start. But when a plan gets put into action, it is subject to the messy reality of roadblocks, changes, mishaps, and uncertainty when working with large groups of people in cross-functional capacities and varying incentives. The ability to handle this dynamic process of building and delivering is execution.