There is currently a small independent one being done in Adelaide where a US Chiro is doing both the fake (control) and then the "tried and tested real chiro manipulations" on patients who have previously not used a Chiro and patients who have. It is observed to try to eliminate as much bias as possible, but he is in it for the scientific method and makes them as close as possible.
From my perspective: If he was trying to skew the results he would make the fake manipulations as obvious as possible. As far as I'm aware this is not the case and his results have been a little demoralising.
In what way?