Since the first Randomised controlled trial in 1946, the RCT has become the "gold standard" for comparing different therapeutic modalities.

The RCT avoids selection bias by randomly allocating patients to placebo or treatment groups. Fair enough don't you think, unless you're a patient.

Imagine you took your car in for servicing and they asked you to sign a form agreeing to have your car randomly allocated into one of two groups, one using your regular oil and another using and experimental oil.

Do you think you might have a preference as to which one was used? Do you think that this might bias your observations of your car's performance? Do you think you might take your car to another garage? Would you be prepared to pay for this service? Would you be worried that your car's engine might seize the week after the service and do you think this anxiety might affect the way you drove your car?

RCTs are predicated on their being no expectation of benefit on the part of the practitioner or the patient. If one therapy has clear benefits over another, there is no need to do an RCT.

Unfortunately this is almost never the case in practice. Barkun et al. published a RCT of laparoscopic versus mini-cholecystectomy in 1992 [1], and he stated that there was a high rate of withdrawl after randomisation, especially in the group for open procedure. He stated that "the trial was stopped because patient recruitment had become difficult".

No clincian would start a trial if they did not have an expectation of benefit of one treatment over another and yet this immediately stresses the outcome and makes recruitment difficult.

Next question, who are you going to recruit? If you want to compare chiropractic with acupuncture for low back, are you going to recruit low back pain sufferers from the general population or from patients consulting a specific clinic.

Naturally, clinic recruiting is easier, that's where the patients are. But those patients have already expressed a desire to be treated in a certain way. Is it ethical to deny them their wishes?

Patients have always, directly or indirectly chosen their own treatment modalities. All the patient wants to know is "Is this likely to work for me?" The truth is, to answer that question, you don't need an RCT, you just need a comprehensive audit procedure.

Barkun JS, Barkun AN, Sampalis JS, Fried G, Taylor B, Wexler MJ, Goresky CA, Meakins JL (1992) Randomised controlled trial of laparoscopic versus mini cholecystectomy. Lancet 340: 1116-1119