Financial Times – could do better

The above tweet [link] popped up in my twitter feed this morning, and it got me thinking.

Not about whether or not Dominic Raab’s claims* were valid.

No, I spent quite some time trying to figure out what that “graph” (info-graphic is probably a better term) was trying to say.

I just couldn’t figure it out.

Now, I’ll be the first to admit, I’m no economist and I’ve never formally studied the subject. But I would describe myself as reasonably numerate and (as I have written before) as a mathematician I am far more interested in the applied side of the subject to the pure; I am used to taking equations, data, charts and graphs and interpreting them. But on seeing the above, I just couldn’t understand it.

First schoolboy error was no axis labels (and no numbers on the y axis at all.)

The headline in bold mentioned house price increase from 1991 to 2016, suggesting a time series graph, where we are accustomed to seeing time flow from left to right.  The title did imply that we were looking at a change over time, yet this makes no sense in the context of the graphic (I’ve given up callling it a graph because, although presented to try and look like a graph for (I presume) gravitas, it ain’t a graph).

I was now becoming increasingly confused.

Having twigged it was not a time series graph, my mind then picked up on a couple of key features of the graphic.  The title said “average house price” and the top number on the x-axis was 275.  I knew that the average UK house price is around £275K (I’ve since checked – its a little lower, but in that ball park) so perhaps the graphic was meant to represent the average house price in the UK? But that made the chart even more nonsensical.

By this stage I was genuinely perplexed. I genuinely had no idea what this tweet and graphic was trying to say.

I could have (and perhaps should have) left it there and got on with my day. But I couldn’t. It was bugging me, so I did a bit of digging to see if I could fathom what the Economics Editor of the FT was trying to convey. It seems I wasn’t alone in my confusion, finding this thread on Reddit

[–]AlcoholicAxolotl1 point

I have no idea what this is trying to show.

[–]easy_pie1 point

I’m struggling to follow what his point is

[–]daveime#Puglife 1 point

Is it big or small?

Who the f$$k knows? Graph with no labels, one axis without values and the other without values or units. What is the Y axis exactly, Hedgehogs per Furlong?

FT Economics Editor, seriously? He must have been absent when they did graphs.

Fortunately, on the same thread, another user, DavidChild, was able to simply and succinctly explain what the Tweeter was trying to say:

Dominic Raab claimed immigration caused a 20% increase in house prices. The bar along the bottom shows percentages, the red and green showing the proportion of the change attributed, and not-attributed, to immigration.

The role of teachers and journalists alike is to educate and illuminate.

This graphic failed to do either – I would have expected more. *Dominic Raab was guilty himself of mangling statistics to suit his own ends and it is right that his (mis)use of data is called into question, but if one of my A level, or even GCSE, students had presented this to me, they wouldn’t have been getting many marks.

In conclusion, Chris Giles, Economics Editor at the FT: could do better.

Posted in Handling Data, Maths Fail | Leave a comment

Hell’s Angles

I stumbled across the above the other day (source) and it made me chuckle, reminding me a little of of this post about cute angels and other mathematical bloopers.

The cartoon above was drawn by Dan Piraro and can be found on his Bizaro website – well worth a visit. By virtue of the fact that you are reading my blog, I’m guessing you are of a mathematical bent (but whether that bend forms an acute or obtuse angle, who knows!) and therefore may particularly enjoy this cartoon of his.

Posted in Geometry | Leave a comment

Nick Gibb – a poor man’s George Osborne?

Back in 2014, I wrote “What a turnip” as the then Chancellor of the Exchequer, George Osborne, refused to answer the simple times table: “what is seven times eight?”

Today it was the turn of the School’s Minister, Nick Gibb, who was on TV announcing his scheme for all eight and nine year old children to sit a compulsory times tables test.

Of course, the inevitable happened: he, himself, was asked a times tables question (what is 8 x 9?) and he, like Osborne before him, refused to answer.

I get why he (and other politicians) choose not to answer – what is in it for them? Nothing.  Get it right and “meh, you should know that”, get it wrong and it’ll haunt you forever, could even spell the end of a glittering* political career.   (* tongue firmly in cheek)

But the presenter, Kate Garraway, skewered him perfectly – in the context of the world of an eight year old, sitting a formal test is as high pressure as doing a TV interview is for a government minister.

To be fair, I don’t disagree with all that the Minister has said and done.  The results for individuals, or individual schools, will not be published, the data will be used as a tool to measure performance in this skill across LEA and the country. And he spoke of the need for instant recall of times tables allowing the freeing up of working memory for other tasks, and I agree with this.  As a maths teacher, I support anything that will promote numeracy and mental arithmetic – a solid foundation in these skills is not essential to future success in mathematics, but they certainly do help. A lot.

Anyway, you can watch the cringe-worthy ministerial squirming on the video below – it should start at the point the question was asked, but if you can spare six or seven minutes, its worth watching the whole interview from the beginning.

Posted in Maths Fail, Numeracy | 1 Response

Come the revolution!

Anyone walking past my classroom of late might have come to the conclusion that I was fomenting a revolution, hearing me inciting my students to

Bring down the power!

The Head can sleep easy in his bed – I am not encouraging the students to rise up, burn their books and storm the staff room. I am merely teaching the rules of logarithms, and the power rule in particular.  You will, of course, be familiar with the rule:

log xn = n log x

but students need to be taught this, so I constantly find myself telling them to “bring down the power.”

When I do, I do like to think of myself as some sort of latter day Lenin, inspiring my students to throw off the shackles of ignorance, to rise up and seize the power that a knowledge of mathematics will bring them!!!

Lenin, calling on his students to bring down the power and submit to the Rule(s) of Logs

Posted in Numeracy | Leave a comment

Large Data Sets – Activities

A year ago, I wrote this blog post, introducing Large Data Sets, a new feature to be taught on the “reformed” new AS and A level specification. Back then, it was a lot of guess work as to how best to use this new element on the syllabus, and how they will be examined in the exams.

One year on, and I must confess, I’m not much the wiser, but time waits for no man and, with much of the “pure” content having been taught the elephant in the room that are large data sets can no longer be ignored.

Helpfully, OCR have published some teaching activities for use with large data sets. They can be found by following this link. I have also uploaded the Word documents and Large Data Set and you can download the directly on the links at the bottom of this post.

They are described as “Starter Activities”, designed to familiarise your students with the large data sets and should take circa 10 minutes per activity. Not sure I agree with this. The activities/discussion points are good – for example, in Activity 5 you might get half your class to be “Team Bristol Mayor” and argue the case for how they have successfully got commuters out of the car and travelling to work by foot or bike, and ask the other half be “Team Paxman” taking down the Mayor’s argument and highlighting car use has increased over the last decade. The statistics can be used to support both arguments and I do think that it is right that we are teaching our students how data can be – and is – used in the real world.

But be warned: these are not trivial activities that you can print out 5 minutes before your lesson – you will want to spend some time looking at the activities yourself before presenting them to the students, even if it is only to understand what the various graphs show as, for example, OCR have not labelled the axis in many cases.

They are also liberal with the use of abbreviations – perhaps this deliberate, forcing the student to consult the Large Data Set to remind themselves with what they mean, but to help you, below are a few of the more common abbreviations, and what they mean:

UMLT: Underground, Metro, Light Rail, Tram

BMC: Bus, Minibus, Coach

MSM: Motorcycle, Scooter or Moped

LDS: Large Data Set

LA: Local Authority

Download the documents:

Starter Activities 1 to 5

Starter Activities 6 to 9

Investigating Bicycle Use (Sampling Activity)

Investigating UMLT Use (Calculating from the LDS)

Large Data Set

Posted in Handling Data, Large Data Sets | Tagged | 1 Response