I used a caliper for many years. It may not be the most accurate. But it is accurate to itself. And with all things being equal such as same caliper, same person measuring etc. It will supply one with a decent result to track bodyfat on a regular basis. For a one off measurement there are more accurate ways to go. But not many are going to go that route to track their bodyfat every week of month. All systems have an error factor as the algorithms they use are form the population at large so the more obese or the leaner some one is the less accurate they tend to be,