Thursday, 22 June 2017

Why researchers need to name their teaspoons

The annual Christmas issue of the British Medical Journal always has at least one 'interesting' paper included. For example, I recently blogged about the study on Pokemon Go and obesity. I recently read this 2005 paper (open access) by Megan Lim, Margaret Hellard, and Campbell Aitken (all from the Burnet Institute in Melbourne) about the Institute's mysteriously disappearing teaspoons. The paper explains:
In January 2004 the authors found their tearoom bereft of teaspoons. Although a flunky (MSCL) was rapidly dispatched to purchase a new batch, these replacements in turn disappeared within a few months. Exasperated by our consequent inability to stir in our sugar and to accurately dispense instant coffee, we decided to respond in time honoured epidemiologists' fashion and measure the phenomenon.
Here's what they did:
At the completion of the pilot study we carried out a longitudinal cohort study. We purchased and numbered a further 54 stainless steel teaspoons. In addition we purchased and discreetly numbered 16 teaspoons of higher quality. The teaspoons were distributed (stratified by spoon type) throughout the eight tearooms, with a higher proportion allocated to those tearooms with the highest teaspoon losses in the pilot study.
We carried out counts of the teaspoons weekly for two months then fortnightly for a further three months.
They then essentially conducted a very simple survival analysis of the teaspoons. They found that:
After five months, 56 (80%) of 70 teaspoons had disappeared. The half life of the teaspoons was 81 days (that is, half had disappeared permanently after that time) compared with 63 days in the pilot study...
If you think this study is inconsequential, think again:
If we assume that the annual rate of teaspoon loss per employee can be applied to the entire workforce of the city of Melbourne (about 2.5 million), an estimated 18 million teaspoons are going missing in Melbourne each year. Laid end to end, these lost teaspoons would cover over 2700 km—the length of the entire coastline of Mozambique—and weigh over 360 metric tons—the approximate weight of four adult blue whales. 
There is an economics aspect to the study. Teaspoons in a common area are subject to the 'tragedy of the commons', as the authors explain:
The tragedy of the commons applies equally well to teaspoons. In the Burnet Institute the commons consists of a communally owned set of teaspoons; teaspoon users (consciously or otherwise) make decisions that their own utility is improved by removing a teaspoon for personal use, whereas everyone else's utility is reduced by only a fraction per head (“after all, there are plenty more spoons…”). As more and more teaspoon users make the same decision, the teaspoon commons is eventually destroyed. The fact that teaspoons were lost significantly more rapidly from the Burnet Institute's communal tearooms (the “commons”) compared with programme linked rooms, correlates neatly with Hardin's principle.
The tragedy of the commons arises because the resource (teaspoons) is rival (one person taking a teaspoon reduces the amount of teaspoons left available for everyone else) and non-excludable (it isn't easy to prevent someone taking a teaspoon). One solution to the tragedy of the commons is to create property rights, which would make the teaspoons excludable. In this case, everyone in the Institute would have their own named teaspoons, with a rule that no one can use others' teaspoons without some suitably dire punishment befalling them.

As with most of these BMJ papers, this one was an interesting diversion. Also, if you haven't ever heard of counterphenomenological resistentialism, I recommend you read the paper and be enlightened.

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