Flipping a coin isn't nearly as random as people think and the outcome can be manipulated, researchers at the University of British Columbia have found.

In their study, 13 ear, nose and throat residents were each asked to toss a coin 300 times and told that the two who achieved the highest percentages of "heads" would get free coffee vouchers.

The participants were instructed in proper coin-flipping technique, and the results were observed and recorded to prevent cheating.

All the participants were able to toss more heads than tails. On average, heads came up 57 per cent of the time. The winner was able to get a heads outcome 68 per cent of the time.

"This study shows that when participants are given simple instructions about how to manipulate the toss of a coin and only a few minutes to practise this technique, more than half can significantly manipulate the outcome," the researchers wrote.

Coin tosses are assumed to be random and impartial, the researchers said, and are sometimes used to decide which treatment patients get in clinical studies.

The study was published in the Canadian Medical Association Journal's annual "Holiday Review," which presents "research with a twist, humorous reflections, witty rants."

Other studies included in the CMAJ's year-end issue include:

  • One that suggests students who get interviewed for medical school on rainy days get lower scores.
  • A study that indicates giving swine flu a scarier name than "H1N1" would benefit public health.
  • A meta-analysis of recent mathematical models of a zombie outbreak.

The researchers in the latter study found that any public health intervention — from quarantine to finding a cure for zombie infection — would delay the inevitable downfall of humanity by only a few days.