By Bill Gates, Special to CNN
(CNN) - Today I released my annual letter. Each year, I reflect on what I learned in the last year through our travels and work with the foundation and how that will shape my thinking over the coming months. This year, my letter focuses on how important it is to set clear goals and measure progress in order to accomplish the foundation's priorities, both here at home and around the world.
Setting a clear goal lets you know what you're driving at: Picking the right interventions that will have the most impact on that final goal, using that information to understand what's working and what's not, and adapting your strategy as necessary. One of the clearest examples of the power of measurement was the work of our partners to support great teachers.
In the past few years, the quest to understand great teaching has been at the center of the public discussion about how to improve education in America. But for the country's 3 million teachers and 50 million schoolchildren, great teaching isn't an abstract policy issue. For teachers, understanding great teaching means the opportunity to receive feedback on the skills and techniques that can help them excel in their careers. For students, it means a better chance of graduating from high school ready for success in life.
But what do we mean when we talk about great teaching? In my experience, the vast majority of teachers get zero feedback on how to improve.