Agree. Level of accuracy goes Smart Scale - Skinfold - Dexa. As mentioned above, there are a lot of variables and variation still with the scale and skinfold. Different brands of scale and calipers as well as how well trained the person is in performing the tests can produce a lot of variation.
I personally have tanita body composition scales at home (Approx $150-$200) and have been skinfold tested multiple times by the same person with Harpenden calipers (Approx $325) and find the calipers come back 3-4% higher than the scales. I'm booked in for a dexa scan next though so it will be interesting to see how they all compare. Here in Brisbane you can get a dexa (including consultation) for $88 first visit and then a follow up scan for about $60.
I'm going into the personal training industry firstly as a PT but with plans to run my own business (I know MWI, another bloody PT to hate on, but we aren't all useless!
) and I will be doing everything I can to negotiate cheap deals on DEXA's and encourage clients to use the most accurate body composition assessment available. Setting fitness goals more often than not centres around 'toning up', getting down to 'x' amount of body fat or a certain weight and fluctuations or inaccurate testing results from cheap scales or tools that may not accurately track progress can be a massive demotivator for people. Badtreefrog, I think girth measurements may be good for people with lots to lose but are too simplistic when using them for people that are relatively healthy already where changes in composition may not actually reflect changes on scales/tapes (someone may weigh and measure up the same or close on a tape/scale but could have totally changed their lean muscle v body fat composition).
While totally out of our control from a fat point of view, the Dexa will show where the person is holding or losing fat while also showing changes in muscle mass broken down into individual limbs, torso and head.