Holiday review. How random is the toss of a coin?
BACKGROUND
The toss of a coin has been a method used to determine random outcomes for centuries. It is still used in some research studies as a method of randomization, although it has largely been discredited as a valid randomization method. We sought to provide evidence that the toss of a coin can be manipulated.


METHODS
We performed a prospective experiment involving otolaryngology residents in Vancouver, Canada. The main outcome was the proportion of "heads" coin tosses achieved (out of 300 attempts) by each participant. Each of the participants attempted to flip the coin so as to achieve a heads result.


RESULTS
All participants achieved more heads than tails results, with 7 of the 13 participants having significantly more heads results (p<or=0.05). The highest proportion of heads achieved was 0.68 (95% confidence interval 0.62-0.73, p<0.001).


CONCLUSIONS
Certain people are able to successfully manipulate the toss of a coin. This throws into doubt the validity of using a coin toss to determine a chance result.
Clark
Matthew P A
MP
St. Paul's Rotary Hearing Clinic, University of British Columbia, Vancouver, BC. matthew.clark@glos.nhs.uk
Westerberg
Brian D
BD
D011897:Random Allocation; D014925:Wit and Humor as Topic