Fed officials say they will be “data-dependent” when it comes to making monetary policy. San Francisco Fed President John Williams feels so strongly about it, he’s even printed up a T-shirt to get that message across. But truth be told, data-dependency is not as objective as it sounds. Data doesn’t dictate policy; it’s the interpretation of data that’s key. What is rate-hike-worthy data to one policymaker is keep-the-pedal-to-the-metal data for another. Take, for instance, U.S. GDP growth. Richmond Fed President Jeffrey Lacker says he expects GDP growth to average 2 percent to 2.5 percent this year, a pace that would justify a Fed rate hike in June. Chicago Fed President Charles Evans expects 3 percent growth this year, and does not believe even that would justify a rate hike until the first half of 2016. So what does it tell you about monetary policy if you see GDP growth of 2.5 percent? Not a whole lot, judging from these two. And the statements of other Fed officials are hardly more helpful. Indeed, as Atlanta Fed President Dennis Lockhart said recently, “I don’t think it is advisable to approach such a decision with rigid quantitative triggers in mind.” Watch the data, sure. But don’t assume the data will tell you much about the exact timing of the rate hike. Monetary policy – it’s subjective. Maybe some policymaker will print that on a T-shirt.