This National Health Statistics Report that we read toward the end of last quarter’s journal club has one of the driest names we’ve seen. But the topic is a fascinating glimpse into the limits of our knowledge about society. How many households in USA have given up their landline phone entirely and only have a cell phone? Well, we answer most questions like that with a telephone survey. Uh-oh. Fortunately the National Health Interview Survey (in my experience, pronounced most commonly as “en-hiss”) is a health survey were enumerators visit households in person, and even though it is about population health, it can also answer this pressing question about technology use (and the potential invalidity of all of the surveys that do not visit households in person, but just call on the phone).