Writing in the Bill & Melinda Gates Foundation’s “Impatient Optimists” blog, Bill Gates, co-chair of the foundation, discusses his annual letter, which will be sent on January 30, according to the blog. “It’s the fifth one I’ve written and I look forward to sharing what we’ve learned in our work at the foundation and how that learning will be applied to our efforts moving forward,” he writes, adding, “This year, my letter focuses on the catalytic role that measurement can play in reducing hunger, poverty, and disease.” He notes that readers can sign up to receive the letter (1/24).