Yeah but accuracy relates to the relative change doesnt it.
If you use the same method of measuring on day 1 and then again 8 months later, I would be less concerned with the accuracy of the ' absolute value ' on day1 and day 1 + 8 months - i.e. is it 96% accurate or 98% accurate etc. etc. against whatever gold standard you which to choose to compare it to - than I would with the fact that the measure indicated I dropped let's say 5 % body fat over that time.
Thats like saying a caliper is really accuarate but it gives a 10% increase in measurement, this can unaccurately categorise someone as obese etc.
I'm not talking about categorization, I'm talking about tracking relative changes in body fat over a given period of time....which I assume is why realworksuks wants to buy calipers of his own....so he can measure his own body fat whenever and as often as he wants.
But more importantly, if its not accurate you cant get relative results so it doesnt make sense to say as long as its relative its fine.
You get relative ' inaccurate ' results...is what you get.
The thought is , if you use a method with only 96% accuracy on day 1 , simply use that same method with only 96% accuracy on day 1 + 8 months. Within that context, focusing on relative changes is fine.
What I'm saying is, if you choose a body fat measurement for the purpose of ' tracking ' your change / eduction in body fat over time, it is the relative change in body fat over time that is likely more meaningful than the 100% accuracy of the reading it is giving you.
If realworksuks chooses calipers as his body fat measurement tool, he'll simply have to live with the fact that this method isn't 100% accurate. If he so chooses, he could also choose something like the circumference method I provided, which in inaccurate as well, but has about the same degree of accuracy as calipers.
If you're going to measure your own body fat at various times over the year - i.e by using calipers - notwithstanding the issue of accuracy, simply use the same measuring tool each time, that's all I'm saying.