Bangers and Mash Up

Here’s the poster from my local Sainsbury which displays what I shall call a “calco”, a mis-calculation, the numerical equivalent of “typo.”

Now £3.79. Was £4.29. Save 70p.

Actually that should be save 50p.

Or should it? All we can tell is that these numbers are not consistent with each other, and so any one could be wrong. Interestingly there’s no way of knowing on the face of it which of the numbers is wrong…might just need to buy some sausages and mash to find out.

But all is not lost. If we want to assume that only one of the three numbers is wrong, then by means of mathematical deduction, we can go as far to say that we would save 50p or 70p.

The fact that this error found its way on to the shop floor of a national chain is no mean feat. The poster will have been through some design, create, print, and probably approval process. Then distributed to stores and then shop floor and no one noticed this simplest of errors. Especially when you consider that the primary objective of the poster would appear to be to make a specifically numerical point.

Also makes me think that perhaps we need a “maths-checker”, the numerical equivalent to a spell checker. It would identify the numbers in prose and check for some sort of mathematical relationship.

National Spend Trend

The Comprehensive Spending review outlines the government spending over the next five years, from 2010/11 to 2014/15. Total spending this year is £697 billion, including £43 billion (6.2%) in debt interest payments.

The emphasis around this has been focused on cuts in order to reduce our debt. However, counter-intuitive as it might be, the key Treasury figures in the CSR show that total spending increases over this period, as does the debt interest.

1. Total Spending… increases…6.2%

Total spend in 2014/15 will be £740bn, an increase of £43 billion or 6.2%. (Given these are such big and critical numbers, it is wonderfully coincidental that this the same as the current level of debt interest payments).

2. Debt Spending…. increases even faster…46%

That total spending includes debt interest, which increases from £43bn to £63bn, an increase of 46% over the five years. So debt interest is increasing faster (46%) than the overall spend (6.2%).

3. Total spending excluding debt… increases more slowly…3.6%

When debt is excluding from total spending, the percentage increase in spending nearly halves to 3.6% (from 6.2%). That’s an increase from £654bn to £677bn over the CSR period.

4. Debt as a proportion of spend…increases…to 8.5%

Over the CSR period, that 45% increase in the debt spending means that debt as a proportion of total spend increases from 6.2% to 8.5% by 2014/15 .

5. Overall…increases, especially debt.

So, spending is increasing in absolute terms, but debt spending is increasing faster, so debt is a bigger proportion of spending at the end of the CSR than at the beginning.

6. And inflation….means reductions.

There will be an inflationary factor to take into account but these overall figures provide a relative picture. But this analysis is based on the figures as presented in the CSR.

The latest inflation figures from the Bank of England show inflation at 3.1%, above the 2% target. Assuming 3% year on year inflation over the life of the CSR means that the £740bn in 2014/15 is actually worth around £657bn in real terms. So compared to the £697bn in 10/11, a reduction of £40bn or 5.7%. Substituting 2% inflation makes this £11bn or £1.6% reduction.

Sources: Bank of England: Inflation Report November 2010. 10.11.2010. HM Treasury: Comprehensive Spending Review 2010. 20.10.2010

Analytical Ecologist

Having been both a producer and user of official statistics over the years - more classically described as the “gamekeeper” and “poacher” roles - this has provided deep insight into both perspectives.

This in fact gave me the luxury of occupying a middle ground, which I can only describe as “ecologist”. In data terms I would define this in simply as...

…understand about today for the benefit of tomorrow.

In fact there is a real balancing act. As with ecology balancing ‘protection’ and ‘exploitation’, and as with ecology seeking the desired state of dynamic equilibrium.

So perhaps a more mature approach would be a coalition, between gamekeeper and poacher for a mutually beneficial dynamic.

What's in a job title?

Or more specifically what words are the the job titles of the top paid public servants?

The government published the roles and salaries of those top 345 public servants earning over £150,000 (pro rata per annum). A total paybill of £58m (More on that another time).

Interested to see for the first time in one place, the variety of titles for the top jobs. So what are the words that are most used to describe the nation’s top public jobs? Well a perfect job for the trusty word cloud.

get the graphic

A strong showing from the generic words me might expect – Chief, Director Executive. Then it’s mostly the terms with more public sector nuance….Officer, General, Secretary, Permanent, Chairman, before a very broad scattering of other more specific roles.

In one relatively simple approach the word cloud typifies the challenge for numerical analysis. Take some words, do the crunching and convert back to words. The wordcloud approach does this so simply and elegantly, and we seem to intuitively understand what’s going on (technically summing and weighting), without having to get into any numbers.

Actually, the world cloud does not provide the message, just the visualisation that allows us to distil the message(s). Overall the datacloud is a neat ambassador for the data analysis challenge.

See Guardian DataBlog: In Full the Highest paid Civil Servants. 1 June 2010

Comprehensive Spending Review - Big Picture

Well maybe a small picture with big numbers on.

The Comprehensive Spending Review outlines the government spending over the next five years, from 2010/11 to 2014/15. Starting with a total government expenditure of £697 billion pounds in 2010/11, increasing to £740 billion for 2014/15.

Big numbers, or so we might think, but that is of course a relative statement which can only really be based on their broader numerical context.

With no one place to get a simple big picture of that broader context, I’ve put together my own one page graphical version.

Drawing on data from HM Treasury, and Office for National Statistics, the £697bn for 2010/11 sits alongside our Gross Domestic Product - the total value of goods and services produced in the country - our national debt, and the sources of government income that funds the annual spending as laid out in the CSR.

"You mean your statistics are facts, but my facts are just statistics"

A great quote from the TV series Yes Minister, which seems to capture both sides of the case for data. Using a small number of words to capture a larger sense of meaning, in the same way that a few numbers can do the same.

Here are a few of the quotes I've collected, which start to illustrate both sides of the case for data and statistics.

We are so often using words to describe statistics but can these series of quoted words, blending the profound with the popularist, and historical and even humorous, capture the essence of the world of statistics....

So the case for....

Statistical thinking will one day be as necessary for efficient citizenship as the ability to read and write. H G Wells

You cannot ask us to take sides against arithmetic. Winston Churchill

Errors using inadequate data are much less than those using no data at all. Charles Babbage

It is by the art of Statistics that law in the social sphere can be ascertained and codified, and certain aspects of the character of God thereby revealed. The study of statistics is thus a religious service. Florence Nightingale

It is a capital mistake to theorize before one has data. Sherlock Homes

And the case against...

If you want to inspire confidence, give plenty of statistics. It does not matter that they should be accurate, or even intelligible, as long as there is enough of them. Lewis Carroll

There are no facts, only interpretations. Frederick Nietzsche

The War Office kept three sets of figures: one to mislead the public, another to mislead the Cabinet, and a third to mislead itself. Herbert Asquith

Facts are stubborn, but statistics are more pliable. Mark Twain

The only statistics you can trust are those you falsified yourself. Winston Churchill.

So not clear cut, useful at times, useless at others. The secret is to be able to tell the difference.