# London’s Real Centre Point

So yesterday afternoon, just before I was about to go out to a meeting and then home, London Live contacted the CASA offices to see if someone was available to talk about a story appearing in Today’s Evening Standard about someone from an Estate Agents deciding that London had a new centre point!! Oh, and it was some bench on Victoria Embankment.

They wanted someone with a bit of spatial nous to come and talk at some ungodly hour this morning, about whether or not this really was the new centre of London. Sadly they contacted us too late in the day (plea to media people – 3.30 in the afternoon for something the morning after is not enough time given meetings and general living of life!) for anyone to appear, but had they have gotten to us a bit earlier in the day, this is what they would have got from me!

Short answer – NO IT`S BLOODY WELL NOT THE NEW CENTRE OF LONDON!!!

Let me explain…

So in the article, apparently Knight Frank “using techniques developed by Army cartographers” (no less!!) have decided that the centre of London is at 51°30’37.6”N 0°06’56.3”W, and this, indeed, is on the Embankment just behind Somerset House, probably near the bench in question.

“But how the hell did these advanced Army techniques arrive at this location?” I hear you ask. Well, London Live sent us through the original press release from Knight Frank, which reveals their methodology. In their release is this picture:

And next to the picture they explain that their calculation is in fact based upon ‘central London’s inner ring road’ (highlighted in red here). So in fact what Knight Frank have done is create a polygon from the central ring road, take the geometric centroid of that polygon and then decide that this is the new centre of London!

Excuse me while I let out a little WTF?!

OK, so the new centre of London is now based on one tiny bit of the central London road network, not the rest of the road network, or the M25 or on any of the other features of the city such as its population or its built up area, or the boundaries of its boroughs or anything like that, just one little section of road? Yes.

I can be sure this is what they’ve done because I have been able to use the same advanced Army mapping techniques (which are remarkably similar to the basic undergraduate GIS techniques I am also familiar with) to reproduce their work:

Here I took some data from Open Street Map on the central London road network, filtered by ‘Trunk Roads’ and selected the central ring road bit I was interested in. Converting this road segment into a polygon (quite easy using the ‘dissolve’ feature in ArcGIS) I could then calculate the geometric centroid of the shape – hey presto the new centre of London!!

Or not. Now I don’t know about you, but I’m not too happy with defining the centre of a massive city like London just by some arbitrarily chosen section of road, that just happens to be sort of circular and sort of in the middle. I think we can be a little more sophisticated with our advanced army techniques!!

What about if we argue that the extent of London is actually all of the Boroughs (and the City of London) that make up the Greater London area? What if we use our army calculation machine (otherwise known as basic maths – seriously, try it here with a triangle) to work out the geometric centroid of the London Boroughs? Surely this would be better?

Ooh look, the centre of London has changed! It’s now on Waterloo road just South East of Waterloo station!

But what if geometric centroids aren’t the best way of measuring the centre of gravity of a place. I mean, sure, they are great for shapes, but London is a bit more than a shape. It’s a city full of people. Are London’s people not important in all of this? Fortunately there are things we can do to take account of London’s people when trying to define a true centre – something that our army friends in all their wisdom failed to explain to Knight Frank!

Us geographers quite often use things call ‘Population Weighted Centroids’ – these take account of where people actually live in an area, and shift the geometric centroid accordingly.

Results from the 2011 Census (probably best estimate of London’s population distribute we have) are released for zones of around 300 people called Output Areas. The Office for National Statistics has very kindly calculated a whole set of population weighted centroids for these areas across England and Wales. What I have done here then, is calculate the mean centre of all of the population weighted centroids for all of the output areas in all of the London Boroughs. Do we get a different centre of London? You bet!!

So as you can see, if we take population into account the centre of London moves yet again and can this time be found somewhere in the Shell Centre just off the entrance ramp to Waterloo Bridge.

Now I could go on – essentially there are any number of ways that we can calculate the centre of London (I could go into the London Travel to Work area, the extent of the Oyster Card zone, the postcodes we use in London, the built up area, but I won’t – for every definition of London Ollie O’Brien talks about in his discussion of ‘Where is London?’, we could define a new centre quite easily), but I would argue that the Knight Frank Centre, being as it is just based upon the geometric centroid of some arbitrary bit of circular road, is certainly NOT the centre of London.

It’s also worth noting that, in case you’d not guessed from my tone, these are not techniques developed by army cartographers, these are basic techniques that anyone who studies an undergraduate geography degree in the UK will learn. And as an undergraduate geography student will be able to tell you, drawing a map or creating a centroid from a polygon is easy once you’ve been shown how – thinking about what you are showing and justifying the decisions you make is the hard bit!

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A post-script

Since I originally wrote the little rant above, I’ve been in contact with Ian McGuinness at Knight Frank who did the original analysis (pre the Chinese-Whisper-Mill that can be the press office, the journalist, the editor, the TV report off the back of the story) – he was understandably a little put out by the tone of the piece above, and this made me realise that perhaps the direction of my ire was not as clear as I though as I thought when writing the blog.

Just to be clear, my beef is with the press hanging on the ‘army techniques’ thing and using this as a lever in the old argument from authority ploy to assert that this is categorically the new centre of London. No Evening Standard and London Live, this is not the new centre of London, this is just one of a number of possible centres of the city which could be defined in a whole range of different ways, depending on what you think is the most important feature of the city. Implying that ‘this is’ rather than ‘this could be’ the new centre by invoking the technical prowess and accuracy of the army is bad form and something that will rattle the cages of academics all day long!

The techniques are standard, the results are subjective, but of course this doesn’t make for a good news story! I know that the headline – “One of many new alternative centres to London proposed” is not as catchy as “London’s real centre point is next to bench on the Victoria Embankment by the Thames” but if you had maybe waited a day before running with the story, I would have been available then to explain this on your TV show!

# Cartograms!!

About 6 months ago I did a bit of work for the conference which became colloquially known as the ‘Two Tonys’ conference – it was a bit of a jamboree held at the Royal Geographical Society to celebrate the long and illustrious careers of Tony Champion and Tony Fielding – if you’re interested the conference website is here. If you’re totally mental, then you can actually listen to my whole presentation on that site, although I really wouldn’t recommend it!

Anyway, for some reason I totally forgot to post the pretty little maps I produced for my presentation, so here they are now…

For those of you who are not down with some of the trickery us geographers get up to when amusing ourselves on dark, lonely, winters evenings, these little blighters are called CARTOGRAMS. Yes, that’s CART-O-GRAM-Z. They’re made by force-feeding digital boundaries, foie-gras style, until those that have been really bad are totally bloated and ready to burst, and those that have been even more bad are neglected and become shrivelled shadows of their former selves (good boundaries are left relatively physically unscathed by this process, but are often mentally anguished at the treatment of their peers).

But why do us sadistic geographers from time-to-time subject these poor boundaries to such inhumane treatment? No, we’re not all closet feeders – it’s actually a pretty nice way to deal with the distorting effects of area size when presenting data for discrete geographical zones. Very often the interesting stuff happening in London, for example, gets lost as London Boroughs are very much smaller than other local authorities in the UK – cartograms help counteract this visual trickery a little bit.

So, after skillfully dodging boundary-rights activists (yes, an occupational hazard for us geographers) and subjecting a selection of local authority areas to some inhumane treatment, here are the results:

Firstly, those who have a holiday home second address are disproportionately located in rich London boroughs (City of London, Kensington and Chelsea)

And where do the stinking rich go on holiday…? Here:

Yes, they all go swanning off to the coast – very nice I’m sure! Well, that is apart from those who go on holiday in the City of London. Yes, I’ve heard it’s really nice there and nothing at all to do with council tax dodging or anything like that.

What? You mean to say that there might be people in England and Wales who take advantage of the generous 50% discount given on second homes by some local authorities who might not be telling the whole truth about what constitutes their second home? That, for example, someone living in a small pied-à-terre in the City of London a couple of days a week (with low council tax) might be trying to fob off their massive country pad (with high council tax) as their second home? Surely no upstanding City employee would be so deceitful? Well, the data might suggest otherwise!

Some of this ‘creative’ home ownership may also be evident in the location of second homes for work:

Well all of this England and Wales holiday home talk is very nice, but what about the serious loads-a-money’s who don’t want to take a chance with the dodgy British weather – where do they all live?

Oh yeah, of course, they all live in London – duh!

So what can we conclude from all of these lovely maps? Well,

• London is the driver of second address activity in England and Wales
• Richest boroughs (City, Kens/Chelsea, Westm, Ham/Ful) are both:
–main address for people with holiday home second addresses elsewhere
–and second address work locations for people with a main address elsewhere in the country
• Home counties dwellers very unlikely to have second home work address elsewhere
• South-West and Wales most popular locations for holiday homes and main home owners with second address elsewhere
• The system appears to be driven by those living (either mainly or partially) in wealthy central London boroughs
• The release of interaction data (Q3 2013?) and small area statistics (Q1-3 2013?) will allow for more detailed analysis:
–Which small areas experience highest rates of multiple address dwelling and what are    the socio-economic impacts?
–What are the socio-economic characteristics of those who own holiday homes / second work addresses?
–What are the flow patterns associated with second addresses? Not just second home owners, but split family relations and detailed student mobility patterns
** No area boundaries were harmed in the making of this blog post **

# London’s Changing Population

A few weeks ago I was approached by BBC London to carry out a bit of analysis in relation to London’s ever-changing and growing immigrant population. Obviously something more interesting came along in the world of London-based topical news, as the stuff I did never made it to air (or at least, even if it did, they didn’t tell me about it)!

Well, the BBC’s loss is the blogosphere’s gain as you lucky people can now get the full, unabridged juicy findings – I hope you enjoy (most of the maps come at the bottom map fans)!

I should probably point out that given the limitations of the data released so far from the 2011 Census (univariate tables in the main), this is pretty light on analysis, heavy on presentation of data. That said, the facts on their own are pretty interesting.

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All of the observations below have been made using data from the 2011 and 2001 Censuses, administered (in England and Wales) by the Office for National Statistics (ONS). These data are available under the Open Government Licence – http://www.nationalarchives.gov.uk/doc/open-government-licence/open-government-licence.htm

# Summary

London is a growing city with over 1 million more inhabitants than there were 10 years ago. A significant amount of this growth has been fuelled by international migration (although even more people arrive each year from other parts of the UK). Consequently, our Capital is now an even more international city than it was ten years ago with 37% of its population not born in the UK (compared to 27% then). Most of the foreign born living in London are from the rest of Europe, but there are significant populations from all parts of the globe.

Examining changes in London’s foreign born population from 2001, people born in Poland show the largest gross increase in numbers, up 136,076 (900%) to 158,300 people. Changes in the numbers of foreign born have also altered the structure of the city’s population, with areas across the city becoming slightly more polarised – foreign born now more likely to located in areas with other foreign born and UK born more likely to be located in areas with other UK born than they were in 2001.

While London can be described as a young immigrant city with almost 20% of the population arriving from overseas in the last 10 years and most of these in their 20s; it can also be described as a city of assimilation – people living in London are only slightly less likely than those in the rest of England and Wales to have a UK passport.

London is a multilingual city with English the main language of only 78% of Londoners (compared to 92% of the rest of England and Wales). After English, South Asian languages are spoken most widely (some 6.5 of the population) with Polish the main language of almost 2% of the population. Of the 22% of Londoners who don’t speak English as their main language, 18% can speak English well or very well. Only 4% have poor English skills, although these people are not spread evenly across the city – in Newham, Tower Hamlets and Brent around 8% of the population have poor English language skills.

Analysis

Country of Birth

London’s Population Composition by Region of Birth

• London’s population has increased by 14% (1,001,850 people) between 2001 and 2011
• While most of London’s population have been born in Europe (76% – which includes those born in the UK) and there has been an 8% increase in the total number of Europeans, the proportion of Londoners born in Europe has declined from 80% to 76%, driven mainly by a reduction in UK born.
• Almost 1 million Londoners were born in Asia in 2011, up 52% from 2001
• UK born (not shown in table) are now 63% of the London population, compared to 73% in 2001.

Top Ten % Increases in Population by Country of Birth

• In terms of the % increase in population (i.e. the number of people in 2011 compared to the number of people in 2001), those born in Romania have the largest increase, followed closely by those born in Poland, those born in China and those born in Scotland.

• The number of people born in Romania in the Capital is not very large at only 44,848 (0.6% of the population). The % increase is large as in 2001 there were only 3,049.
• The largest increase in those born abroad has been those born in Poland – an additional 136,076 are now living in the Capital. A rise since 2001 from 0.3% of the population to almost 2%
• The numbers of foreign born people have risen across England and Wales since 2001, but compared to the rest of England and Wales, the proportions of foreign born in London have increased by more.
• There are fewer UK born people living in London now (5,175,677) than there were in 2001 (5,231,701). The largest decrease has been those born in Northern Ireland (75,908 fewer).

The maps below show the location quotients of the UK born population within London – these show population concentrations with areas >1 above the average for the city and <1 below average.

UK born population are more heavily concentrated in the outer boroughs, with a below average presence in the ‘Inner London’ boroughs.

• Between 2001 and 2011, these spatial concentrations have become more polarised, with concentrations becoming even heavier in the outer boroughs and even less heavy in the inner boroughs (see the animation .wmv file below for animated transition). This is partially a consequence of the far lower proportion of UK born in the city acting to intensify concentrations, although even when accounting for this, the gap between lowest and highest concentrations is increasing slightly.

LQTransition

• The change map above shows how and where the concentrations of UK born population are evolving in London. ‘Strong’ shows where above average concentrations of UK born were in 2001; weak, where concentrations were below average.

Passports Held

• London’s proportion of people with UK passports (71.2%) is not dissimilar to that of the rest of England and Wales (75.7%), despite a larger % of people being born abroad. This suggests that whilst London is a city of immigrants, it is also a city of assimilation.
• Less than half of the people in London compared to the rest of England and Wales (7.8 vs. 16.9) have no passport – indicative of the volume of internationally mobile people within the city.

Length of Residence in the UK

• 63% of London’s population were born in the UK (compared to 87% in the whole of England and Wales)
• London is home to 40% of the people living in England and Wales who were not born in the UK
• 4.5% of people living in London arrived in the last 2 years, 10% in the last 5 years

Year of Arrival

• Year of arrival data confirms London’s status as a city of new arrivals – almost 20% of the population of the City arrived here in the last 10 years and almost 3 times that of the rest of England and Wales.

Main Language Spoken

• English (or Welsh) is the main language spoken by 78% of Londoners (compared to 92% in the rest of England and Wales).
• South Asian languages are, after English, the most frequently spoken with ½ a million Londoners (6.5%) defining it as their main language.
• Polish is the third most popular main language spoken with almost 2% of Londoners speaking as their main language.

**See the maps at the bottom of this post for the spatial concentrations of these languages in London**

Proficiency in English

• A higher proportion of people living in London cannot speak English well or at all, than in the rest of England and Wales (4% vs. 1.6%)
• There is a distinct geography to poor English language skills in the Capital…
• Three boroughs (Newham, Tower Hamlets and Brent) have over double the average rate of those who state in the Census that they cannot speak English well or at all – up to 8.2% of the population in these areas.
• Location Quotients compare distributions of a particular variable with the national average. A score greater than 1 indicates that the area has a greater share of that variable compared to average. The map below highlights areas of London where people with bad or no English language skills are concentrated:
• Poor English skills are particularly prevalent in Newham, East Haringey, South Waltham Forest, Tower Hamlets, South-East Enfield, Brent, Ealing, South Hillingdon and North-West Hounslow. Poor English skills are less prevalent in South London.

# Age of arrival into the UK

• For those not born in the UK, the most common age group of arrival is the 20-24 age group (in line with the age of peak migration across the world). People in this age group comprise around 22% of all migrants arriving in the capital
• 41% of all migrants arriving in the capital are in their 20s – although this is not much higher than the 38% of migrants in the rest of England and Wales.

# London’s Religious Concentrations – Part III

OK, I wasn’t going to spend any more time on this, but as always once you get started with something like this, it’s hard to put it down!

This post has been inspired by very similar questions posed by Nicola Shelton and Colin MacInnes on my Facebook wall – the gist was  “this is all very nice, but have you thought about religious diversity?” i.e. where are the places with the most different religions and where are the places where it’s all pretty homogeneous?

After a bit of thinking out loud on my facebook wall about how to calculate such an index, I ended up doing what most sensible people do these days – I had a bit of a Google around! Several years in academia have taught me that if you have a bit of a conundrum, chances are, most of the time, someone else will have had a very similar problem and posted an answer on the web!

So it turns out, diversity is something ecologists are pretty into – they bloody love looking at whether or not areas contain a diversity of species and have developed/plundered from other disciplines (like us geographers love to do) a plethora of indices to quantify the diversity phenomenon. One of these is the Gini-Simpson index (sometimes described as just “the Simpson Diversity index” or similar – see this Wikipedia page for a description of the difference). I could’ve also used Shannon Entropy as a measure, but much of my life for the last 2 years has been to do with Entropy maximising, so I thought I’d leave it in the bag this time!

The Gini-Simpson index is a measure of the diversity of an area. It takes into account the number of different groups in the area as well as the relative abundance of those groups. The index can be calculated using the following formula:

$D_{i}=1-\left(\frac{{\displaystyle \sum_{j}}\left(n_{ij}\left(n_{ij}-1\right)\right)}{N_{i}\left(N_{i}-1\right)}\right)$

where  $D_{i}$ is the Gini-Simpson diversity for area $i$

$n_{ij}$ is the total number of people in area $i$ who are classified in religion $j$

and where $N_{i}$ is the total number of people across all religions $j$ in area $i$, or:

$N_{i}={\displaystyle \sum_{j}\left(n_{ij}\right)}$

The index ranges between 0 and 1. 1 represents an infinite diversity, 0 represents no diversity (or complete homogeneity, if you’d rather).

I calculated this index for each output area in London, and it produces some rather pretty maps. In addition, I also calculated a standardised ratio which enables you to look at the religious diversity of an output area, compared to the average diversity for the whole City. Of course, the denominator need not be London, but could easily be England and Wales, or the whole UK.

I’ve not seen anyone talk about using a standardised ratio anywhere, so in honour of Colin sparking my interest, I shall dub it the ‘Colin-Gini-Simpson or Colin-Diversity Ratio’. If you like algebra, the equation for calculating the Colin-Diversity ($CD$) Ratio for area $i$ is:

$CD_{i}=\frac{D_{i}}{D}$

where

$D={\displaystyle \frac{\sum_{j}\left(N_{j}\left(N_{j}-1\right)\right)}{T\left(T-1\right)}}$

where

$N_{j}={\displaystyle \sum_{i}n_{ij}}$

or the total number of people in each religious group across the whole city.

And

$T={\displaystyle \sum_{i}\sum_{j}n_{ij}}$

or the total number of people in the city.

Yes, yes, I know, that’s enough tedious algebra – WHAT ABOUT THE MAPS?!?!?! OK, so here we are. First up is the standard Gini-Simpson map of religious diversity. Should probably note that the reference index for the whole of London is 0.699 (remember, 1 being infinitely diverse, 0 being completely homogeneous) – so pretty diverse, as we might expect. The range of values is quite large as well, with the least diverse output area (0.19) E00004097 – which is in Bromley in South London.  The most religiously diverse OA is E00010619, which is the area to the South of Canons Park in Harrow, north London.

As might be expected, with the higher LQs for most religious groups in North London, the most religiously diverse areas are in this half of the city, with much less religious diversity in the South.

The next map is the Colin index, which shows quite neatly areas which are above or below the average diversity for London:

There’s a bit of negative skew in the data, with more OAs being less religiously diverse than the Gini-Simpson score for the whole city.

And one final map, just to finish this whole thing off – this map shows the most popular religion by OA, i.e. were you in that output area, this is the religion that most people you come across will be – enjoy!

***Oops, just spotted an error (mine!) Where it says Buddhist, is should really be Hindu – will fix the map on Monday, but the pub beckons now!!!)***

# London’s Religious Concentrations – Part II

OK, as I still had ArcGIS cranked up on my machine and this appears to have been a popular blog topic, here are a few extra maps to finish off the London’s religions post.

So, in order of whether or not adherents are likely to enjoy all traditional flavours of monster munch, I shall proceed…

Jedi

Interesting patterns of concentration for the Jedi here – essentially they are not very concentrated at all. Not suffering from the internal dogma or external persecution which has led to the clustering of a number of other religious groups in the capital (plus their ability to employ rather useful ‘mind tricks’ on property gate-keepers who would have otherwise encouraged them to rent property in areas where ‘their lot’ were already starting to cluster) the Jedi are perhaps the least spatially concentrated religious group in the capital. A case study in diversity and multicultural integration if ever I have seen one!

Religion not stated

“Yeah, screw you Nanny State – I ain’t gonna give you my deets! You ain’t gonna know my shizzle!” Or something like that. Yes, some people would rather not say if they believe in any hocus pocus or not. How knows why this is? Maybe disdain for the government and its Census form. Maybe they are secretly embarrassed about believing that the words of 20th Century science fiction writer are anything other than a total load of rubbish. Either way WE STILL KNOW WHERE YOU LIVE! In Camden, Islington and Tower Hamlets, by all accounts… Yes, the ‘rather not say if you don’t mind’ brigade are real central London dwellers. I would suspect that those in Tower Hamlets may have different motivations for not saying than those in the leafier north London suburbs, but the patterns probably warrant some further investigation at some point.

Buddhists

Buddhists are a bit like the Jedis – all over the place! Lets just hope the Jedi don’t start training the buddhists (they’re both a bit Zen, so probably would find some common ground) or the number of light-sabre related admissions in London A&E departments may rise quite rapidly…

Sikhs

Still some pretty high concentrations in West London (Hounslow, Ealing) and in the Redbridge – areas with traditionally high concentrations of this group…

Hindus

Similar concentrations to Sikhs in Redbridge, but also high concentrations in Brent and Harrow.

Jews

Jewish population in London are still heavily concentrated in the Northern-most boroughs. Location quotients are particularly high at their highest (well over 20 and up to 60, compared to only about 7 at the maximum for the Muslim population in London)

So that’s it folks – hope you’ve enjoyed the maps! Until my next period of procrastination…

# New Census data – London’s religious concentrations

So, today the ONS treated us with some brand spanking new Census data, all the way down to Output Area level (zones of about 150 to 500 people).

The data contains some interesting headline facts and some fascinating spatial patterns…

For example, fact fans, in London there are 173 people for whom ‘Heavy Metal’ is their religion. There are 85 Druids. Only 64 Scientologists (which is surprising considering how often they bug me as I walk down Tottenham Court Road!). 5,637 Jedi Knights (although no Sith). 27 total nut-jobs who are into Witchcraft – exactly half the number who are Satanists.

As always, it’s a bit of a race for the geography geeks to get their maps out first – I’m sure James Cheshire has probably already beaten me to this and got his map in the Evening Standard already, but here are some of my first rough and ready efforts…

What have I chosen to map? Religion of course (what else?!)! It’s always quite an interesting thing to look at, especially in London and especially since the enlightened now count for a much larger percentage of the population than ever before!

I’ve decided to use Location Quotients –  First introduced to me quite a few years ago now by the legendary Phil Rees (the actual material he used can still be found online here if you’re interested) – as they are quite a nice way of getting to grips with the relative concentrations of different groups across an area.

The LQs I’ve calculated here use the whole of London as a base, with values <1 (grey) indicating a lower concentration in that particular OA for the variable in question, and values >1 indicating a higher concentration.

So what have we got? Well, as a card-carrying atheist of course I’m going to be interested in where the godless are concentrated:

Far more godless in South London by the looks of things…

And Christians?

Not very many in Islington and Camden – not sure how this compares with the concentrations of Satanists and Heavy Metallers (and I doubt a causal link!)

And the last one for now – Muslims…

Apologies for no real analysis as such, but I’m sure we’ll see plenty emerge as more people get their mitts on the data… I may also post a few more tomorrow if I have time!

# Working paper fun

Just to prove that I’ve not been twiddling my thumbs for the last 12 months, here’s the first (of hopefully many) working papers to come out of the ENFOLDing Migration stable…

Alan Wilson and I have been working on a new family of Spatial Interaction Models for estimating inter-regional migration flows in Europe. We’ve developed a new multi-level model which uses internal migration data at the regional level and international migration data at the country level to model international regional level flows.

Once I’ve finished tidying up the code, I’ll post the full model here too for people to play with – at the moment though, you’ll just have to make do with the paper, which can be found here:

http://www.bartlett.ucl.ac.uk/casa/pdf/paper175.pdf

And here’s a pretty picture from it!

# New paper from me and the sad end of an era…

Yes, British migration classification fans, it’s the moment you’ve all been waiting for – publication of the CIDER Migration Classification paper! *Cue delirious cheering, whooping, hollering and cries of ‘get in the hole!!’*

This most recent product of my blood, sweat and tears – co-authored by John Stillwell – can be found in the latest edition of Population Trends. I say latest, but I should also say final, as sadly after 36 years of publication Population Trends is from today, no more. In 2010 the Office for National Statistics took the decision to cease regular publication of all of  its journal titles – I can only speculate the victim of the severe cuts being enforced across the public sector currently.

The Autumn 2011 issue really does mark the end of an era and I will be sad to see it go, especially as I think I can safely say that it is the journal, above all others, that has been the source of useful and practical research during my academic career.

# Iterative Proportional Nitwit

Iterative Proportional Fitting? That old chestnut? Haven’t people been banging on about that for hundreds of years?! Well, about 70, but I guess some of the old ones are the best ones… (Deming and Stephan for all those pub quiz fans out there!)

Anyway, I recently stumbled across IPF again in the way that people who work with data matrices do from time to time. I also realised that there’s not a whole lot of useful generic programmes out there for you to carry out this pretty useful procedure, and like a total nit, I’ve been doing it the hard way for a long time. Therefore I have spent the last day or so writing a nice little bit of VBA (arrghh, not Microsoft?! Yes! And it even runs in the much maligned but fantastic Excel). The program will take in data in either matrix or paired list format and will run IPF to update the interior cell values to a new set of column and row margins whilst maintaining the original ratio structure of the table.

I think Paul Norman produced a similar program in Excel a few years ago, but if you can find it anywhere on the web you’re a better Googler than me! Hopefully this programme improves Paul’s a little with the flexibility for matrices and paired lists and with it taking advantage of the increased number of columns available in the latest versions of Excel. Also, this will be freely available to download from here from now on. If you’d like to use the program, it can be downloaded from the link below:

http://dl.dropbox.com/u/8649795/DESKTOP_IPF.xlsm

Enjoy!

Oh and here’s a nice picture that my ENFOLD-ing colleagues will enjoy!