16 December 2016

Christmas: A research & statistics perspective

David Mann from the College research team examines the numbers surrounding Christmas from a research and statistics perspective.

According to the statistics, (that's an ominous way to begin any sentence) there were 10 million turkeys eaten in the UK last Christmas. That's 2 turkeys for every 5 households, or 1.5lbs of turkey for every person in the country, whether they like turkey or not. Is that a lot of turkey? Well, if it were a single bird it would be about the same height as the towers at Canary Wharf, weigh 45,000 metric tons, and it would take 3000 years to cook (at gas mark 4), although I imagine it might be quite dry at that point.

However, we shouldn't let ourselves be misled by apparently big numbers without having some comparison. The UK chomps its way through 800 million chickens every year. Allowing for the difference in weight between the two birds, that's around 30 times more chicken meat eaten than turkey. So a single chicken that size would not only dwarf our giant turkey, but also act as the inspiration for a multitude of Godzilla vs Chicken-Monster films, along with a Channel 5 series of "When Chickens Attack!".

Although giant turkeys are pure fantasy, the existence of Santa Claus is never in doubt. Nevertheless, we should re-visit our basic assumptions regularly just in case we are misleading ourselves. One of the earliest internet posts to go viral looked at the physics of Santa Claus. Assuming that he doesn't keep popping back to the grotto to re-stock his sleigh full of presents, his sack weighs around the same as a fully loaded, ocean going super-tanker. He will also need to keep up an average velocity around 3,000 times the speed of sound to visit the 800 houses per second required to complete his task. At this speed, Santa will have to get a spacesuit, because if he flies moderately close to the ground then the shockwave from the nine reindeer, Santa, and his oversized sack of presents will destroy buildings, start forest fires, and lay waste to any part of the planet he passes over. In this case, Santa wouldn't need to come down the chimney, as any house he visited would be reduced to a pile of smoking dust, albeit one that's left with a gift wrapped box of Lego and a Winnie the Pooh cuddly toy. The reindeer themselves must be extremely powerful, because to get up to this speed in a reasonable time would require the energy output of all the power stations on the planet. So we are left with the inevitable conclusion that either Santa is able to overcome these physical problems (perhaps by employing quantum tunnelling effects), or maybe he receives a distributed source of help which is not mentioned in stories of his exploits.

Perhaps the physical problems generated by Santa's task have led some to doubt his existence (despite overwhelming evidence that millions of presents get delivered and someone has to do it). An automated phone poll in 2013 of registered US voters found that 43% (n=741) of the respondents believed in Santa Claus, 32% said that it was a "verifiable fact" that Santa is white, and 33% said he voted Democrat (with 47% unsure how he voted). These results appear to be at odds with another poll carried out at the same time which found that only 20% of children over 11 believe in Santa. This seems to imply that older children do not believe in Santa, but don't tell their excited, believing parents that he doesn't exist in case it spoils the fun.

For opinion polls results it is advisable to go back to the source material to find out exactly how the data were collected, who was asked, what the questions actually were, and how they were "framed". As an illustration of how important it is to go back to the source, do you know how many wise men turned up at the nativity? I'll give you a minute to think about it and consider whether this is a trick question or not…  Of course the Bible doesn't mention how many wise men there were. Clearly the lower limit is two, and a number more than forty would probably have been commented on. The wise men turned up with three gifts, but that may just imply a lack of imagination (which further implies they were wise, but not creative).

Issues surrounding the behaviour of Santa are of great importance to the College, especially as Christmas generates so much work for police forces across the country. Next year we will be conducting a randomised controlled trial to see whether Santa really does leave varying amounts of presents based on whether children have been naughty or nice. We will be randomising children to receive either a box of matches and directions to a famous public building, or a year's membership to their local scouts/guides and a copy of Nelson Mandela's autobiography. Next Christmas we intend to analyse the distribution of presents in the 2 groups (although this design may be modified once we receive the comments from peer reviewers and the ethics committee). And, to truly understand the social dynamics surrounding Christmas, I will be undertaking an extensive ethnographic, participant observation study in my local pub.  Results in the New Year.

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A selection of sources which I may or may not have used, and which may or may not contain accurate information which I may or may not have distorted for humorous purposes.