How we learn to stop worrying and love statistics

Just a brief one today. MORI has recently done a poll chiefly on the subject of Britain’s nuclear deterrent. Now, here at mySociety we don’t have any political views, so no comments on The Bomb itself; but MORI did ask another question which intrigued me:

And which, if any of the things on this list have you done in the last two or three years?

What How many
Presented my views to a local councillor or MP 14
Written a letter to an editor 6
Urged someone outside my family to vote 16
Urged someone to get in touch with a local councillor or MP 12
Made a speech before an organised group 11
Been an officer of an organisation or club 8
Stood for public office 1
Taken an active part in a political campaign 3
Helped on fund raising drives 20
Voted in the last general election 68

So, 14% of British adults have “presented [their] views to” a councillor or MP in the past 2–3 years. I presume most people will have interpreted the question as including writing to their MPs; that gives us something like 6 million letter-writers over that period. On WriteToThem, about 75% of messages are for MPs, so if those 6 million people sent one letter each over the three years, that works out as about 2,000 messages/year/MP, or about ten per working day.

That’s a lot lower than typical estimates I’ve heard (~50/day/MP). Of course, the poll asked about people rather than letters, so doesn’t account for people sending several letters over the given time period. However, judging by the WriteToThem data, that’s not all that significant an effect:
[Plot of number of letters per author in WriteToThem, image gone]
— something like 90% of letters sent through WriteToThem to MPs and councillors are the only ones sent by that author. (Note that this measurement is quite crude; in particular, I have identified two letters as being from the same author if they share a common email address. Also, since we remove all personal data about authors from messages after a little while, it only shows a few weeks’ worth of data. A further complication is that if an MP or councillor responds by email and the constituent sends a further email, they’re likely to do it by replying to the email, so not showing up as a further communication on that plot.)

Anyway, if the crude data from WriteToThem are characteristic of all mail received by councillors and MPs, then MORI’s estimate of the number of people communicating with their MPs seems pretty low. Thoughts?


  1. “it only shows a few weeks’ worth of data” kind of invalidates things. I write to my MP about 1 or 2 times a year. Which could be 6 letters in 3 years, but I would show up as having only written once in your graph.

  2. Well, not wholly invalidates, but it is definitely a limitation. Now, suppose that all of the people who we saw writing one letter were writing twice per year. That only roughly doubles our estimate, to ~20/year/MP.

  3. I thought 14% was very high!

    Surely of those 50 a day received by MPs a very large proportion will be from members of the public writing in the capacity of a business, or charity, or other organization?