Ben Goldacre, The Guardian, Saturday 13 March 2010
“2,000 bugs taking a ride in every train compartment” said the Daily Mail. “Cockroaches cluster on trains“, scuttled the Telegraph. “Commuters share trains with 1,000 cockroaches, 200 bedbugs and 200 fleas” said the Evening Standard. The figures were all very specific and very frightening.
“Rentokil say they also discovered that a bus was home to 500 cockroaches, along with dozens of fleas and bedbugs,” explained the Standard. Those disgusting trains are even worse. “Research by pest controllers Rentokil shows that, on average, a single train compartment houses a staggering 1,000 cockroaches, 200 bed bugs, 200 fleas, 500 dust mites and 100 carpet beetles,” said the Mail.
These figures are very specific, and they do all sound a little bit on the high side. Where did they come from? “Staff at Rentokil sprayed insecticide throughout the carriages of a train and a bus and then counted the bodies of insects.” said the Standard. Savvas Othon of Rentokil explained in the article: “The bus we studied was within the M25”.
But Transport for London say they’ve had no contact with Rentokil, and that no such study has been done on their vehicles. I asked Rentokil for more details on what vehicles they had studied, where, and how, what was counted, how the bugs were collected, and so on.
After a bit of prodding, their PR company Brands2Life explained how these bugs were counted. No buses were studied, and no trains were studied either. How did people get the wrong end of the stick? What was that about with Savvas Othon? I have no way of knowing. Brands2Life and Rentokil both declined to show me what they sent to journalists, but in any case, contrary to what was said earlier, wherever it came from, these numbers did not come from measurements and counts, they are actually based on a “theoretical model”.
Models are handy. They’re a simulation of reality, based on a series of assumptions. Rentokil’s model for the number of bugs on trains and buses made some interesting assumptions, and you will have your own view on whether they make for a reasonable approximation to the real world.
They assumed, for example, that the railway carriage or bus was left alone, by itself, in isolation. They assumed this isolated carriage was helpfully furnished with a plentiful food supply. They assumed that the ratio of male and female bugs was perfectly optimal for breeding.
They assumed – surprisingly for anyone involved in modelling populations, surprisingly for anyone, really – that the population of bugs would be left entirely unchecked, with no external factors to control the mortality rate. They assumed that the siding or garage was controlled at a constant temperature all day and night, with no extremes, they assumed there were no trampling commuters, no cruel vaccum cleaners, no anything. In fact they assumed there was no cleaning, ever, and no passengers, ever. This was their model of insect populations on commuter vehicles.
“On the above basis” Rentokil’s PR explained to me: “it is possible that the stated numbers of cockroaches and bed bugs/fleas could live on a train carriage or bus.”
You will have your own view on whether you could trust an organisation that makes assumptions like these in estimating the “average” population of a bug. But it’s somehow unseemly that Rentokil, a company with £2,356m revenue, a 54% increase in profits in 2009 to £166m, and poised to pay £90m in bonuses to its top 3 executives, feels the need to make everyone afraid of public transport on a PR whim. There is also the ugly thought that Rentokil will do more business if they can make everyone scared of bugs on the bus.
And on March 2nd, the day before the cockroaches press release, Rentokil announced the single biggest ever contract in the history of their business: £200m over 5 years with London Underground.
Please send your bad science to email@example.com
Appendix 1: twits
Rentokil have engaged in some seriously surreal PR activity on Twitter during my digging on this story, largely around whether they would give me the information they sent to journalists. The best bits were when they tried to suggest that they were actually being all open and stuff.
You can pick up some threads here (read backwards I guess), and if there’s a better timeline of quotes anywhere I’ll link to it. This was a textbook case of PR fail, but I’ll spare the details, as it’s possible you had to be there in real time and with popcorn. The slightly odd and chastising tone of this post from Rentokil’s blog might help you form your own opinions about the person who has been left in charge of the Twitter login for a £2.4 billion corporation.
Appendix 2: PR
In the generality (and I mean that very seriously, I’m not talking about Rentokil or my article here, but the wider issue which comes up a lot) I think there are a few things that companies and PR people need to learn about the internet. When there was only olde worlde large scale media, covering only big stories, where space is short, and the product is a single final publication on paper, PR is different. Even in a truly dismal situation, you can often do a bit of superficially plausible PR that someone will stick on the end of their mildly critical article, and then you can run for it. If your response turns out to be flimsy, the paper won’t bother coming back at you, or returning to the issue, because that wouldn’t interest a million people.
With the internet, page space is infinite, and people will post any old nonsense on the grounds that it might be interesting to someone somewhere (and I’m very glad of it). There are bloggers, of course, who will get inexplicably fascinated by a single issue, and follow-up every development, no matter how obscure. But there are also random passers-by, who might use Google to double check your utterances on Twitter, in 10 seconds, while they wait for the kettle to boil, just out of interest. Then they might post the results, with a single keystroke, on Twitter, in a blog comment, just because it adds a little to the story, and someone else might find that, and build on it, and so on. I’m rambling, but I do think it’s interesting how the web makes the environment very different for everyone in PR who hopes that vagueness and disinterest will smooth over their rougher edges.
Update Friday 21:30
Someone has just sent me this:
Interestingly, I’ve also been contacted by someone from a major public transport organisation. They told me that Rentokil promised to clarify on these foolish figures to journalists over a week ago, when the story was in the news, but then they didn’t. So it’s fun to see that Rentokil were suddenly able to post and clarify these issues. Late. One Friday evening. A week and a half later.