Learning Curve

In this post I described how I had reduced my hours to a 4-day week, to allow me to have a day a week in which to pursue various projects, paid or otherwise.  I haven’t been quite as productive as I would have hoped, but it is still early days.  My major accomplishment so far has been a sudden dollop of self-knowledge.

I consider myself a reliable person.  At university, I always got work in on time and to an appropriate standard (not always great, but good enough).  My salaried work is in project-based consultancy – specific deliverables by a specific deadline.  Sure, things get held up sometimes, but that is just the way it goes.

I thought that this would stand me in good stead for working independently.  So far it hasn’t worked out quite as well as I would have hoped but I have worked out why.

I am reliable when other people rely on me.  If I haven’t made a promise to someone else, it may well not get done.

This isn’t as bad as it sounds for someone with aspirations to work independently.  Firstly, if I have clients then they are relying on me so that is not a problem.  It gets tricky around “development” projects, when I am doing something for its own sake or with an indeterminate timescale or uncertain pay-off.  Like this blog!  Now that I have realised this about myself, how do I respond to this new information?  I need a strategy that goes with the grain of my character.  Thinking to myself “Just get on with it” doesn’t work.  I need to make rash promises and commitments to as many people as possible, so that I feel that I would be letting them down (or at least making myself look stupid) if I didn’t deliver.

To this end I promise you, dear reader, to post three times a week here.  If I don’t, tell me how disappointed you are…

The second-hand economy

I was looking for some information on the size of the online market for second-hand items, because I wonder if the efficient market that the internet provides (as opposed to local charity shops etc) has a significant effect on reducing how much we throw away and how much new stuff we buy.  I didn’t find that information so I will have to leave it for another day, but I did find this article from Marketing Week which I thought was worth a quick comment.  It quotes the awesomely-named “Ralph Risk”.

The rise of eBay and the economic slowdown has seen second-hand goods reach new heights of popularity. But age, sex and income still dictate the types of used items we buy.  In these cash-strapped times, it will come as little surprise that more people than previously are willing to consider buying second-hand goods. But an exclusive study conducted for Marketing Week by Lightspeed Research reveals that every single adult in the UK – based on a representative sample – would now consider buying something second hand

No.  The rise in popularity of second-hand goods has seen eBay reach new heights of popularity, not the other way round.  And is it news to suggest that “every single adult” (hey don’t worry – it’s a “representative sample”!) would “consider” buying “something” second-hand?  It is certainly a relief to know that not one adult in the UK is so blinkered that they would never, under any circumstances, even consider buying anything whatsoever that had been previously owned.

When asked to nominate which items – from a list of their own second-hand past purchases – they buy most frequently, 38% of respondents report that books are their most frequent second-hand purchases.

Last year, the missus and I had a bit of a clear out and put some second-hand books up for sale on Amazon.  It was soon obvious that unless you have something collectable, hardback, or in mint condition then used books are something of a commodity and barely worth selling unless you have a very efficient operation.  This certainly didn’t include us.  All good for the consumer though, which is nearly all of us.

The key motivator overall for consumers buying used items is unsurprisingly saving money, followed by people simply loving a bargain.

Same thing, no?

Men are much more likely to say saving money is their main motivation, while women are much more excited about getting a bargain.

Same thing, no?

Fee Gilfeather of Oxfam said that:

We’ve seen an increase in demand for second-hand items over the past 12 months as shoppers seek value for money in the recession. The downside is that our stock donation levels have fallen by around 12% as people buy fewer new items.

For me this is the most interesting point.  Second-hand sales both compete against and rely upon new sales.  Lower sales of new items implies a greater demand or potential demand for second-hand items, but also implies a lower supply.  This sounds like a recipe for rising prices in charity shops – increased demand, reduced supply.  Conversely though, given the ease with which you can sell your second-hand items online rather than giving them to charity, does this mean that the quality of items available in charity shops will decline?  Where once you would give both your tatty old clothes and a couple of nicer items to Oxfam when you were done with them, you might now sell the good stuff leaving Oxfam with the tatty stuff.  If this reduction in quality counteracted the different supply/demand noted above, you might expect prices in charity shops to remain roughly the same, but quality to decrease.

Finally, I wonder what the impact has been in the last 10 years or so of shops like Primark selling their low-end stuff at something like charity shop prices?  That’s for another day though.

Soaring Expulsion Rate is a “Blip”

This weeks Birmingham Post has an article entitled “Soaring expulsion rate is ‘blip’”.  Apparently:

A huge increase in the number of children permanently expelled from Birmingham schools is an unexplainable one-off blip, education chiefs have insisted.  Just over 80 pupils were regarded as so disruptive that they were removed from mainstream education by city head teachers in a single term.  The figure, for Autumn 2009, represented a 40% increase on the same period in the previous year

By the standards of some reporting of statistics, this isn’t a bad article.  However, it still provides no context, without which we cannot make a judgement.  For example, what if the history of school expulsions in recent terms was like this?

Very little change, and then the rate shoots up.  This could be something serious.  However what if it was like this?

Suddenly, the jump is just part of a history of wide fluctuations.  Also, notice how in both graphs the penultimate data point is missing.  The article tells us that over 80 (I called it 81) pupils were expelled in Autumn 2009, a 40% increase “on the same period last year” i.e. Autumn 2008.  What was the figure for Spring 2009?  We have no idea, it could be anything.  For all we know it could be higher than 81, in which case the most recent figures are part of an encouraging trend.

Finally, what is the figure in percentage terms?  I couldn’t immediately find the school age population of the city so I crunched some numbers.  Wikipedia tells us that in the 2001 Census the population of Birmingham was 1,113,000.  Of these, 23.4% were under 16.  This calculates as 260,442.  If we assume that there are equal numbers in all of the year groups under 16 (obviously false, but I’m a busy guy), then we can say that 11/16ths of this figure are at school – about 180,000.  So, last term, about 0.045% of pupils were expelled, against 0.031% a year before.  Obviously these population figures are derived from figures that are nearly 10 years out of date, and have rounding errors and incorrect (but reasonable) assumptions thrown in.  Nevertheless, the figure is very very small.

When reading an article about figures, always ask yourself what you are NOT being told.  Not that you are being mislead, but what different backgrounds could actually cast the results in a different light, as we have done here?

How (not) to get to Mars

This is the beginning of an article I started writing a few months ago, mostly as a kind of “brain dump” exercise, which I thought I would post here.  It’s a theme that I will be revisiting.

I am not a rocket scientist so I could not comment definitively, but after several years enthusiastically following the debate on how or whether to send humans to Mars, it seems that we have the technical know how to do so if we choose.  Where the whole endeavour fails of course, is money.
The obvious source of money is government.  In a limited sense this worked extremely well to get people to the Moon in the 1960s and 1970s.  The goal was set in 1962 with an extremely limited amount of technical experience and acheived a mere 7 years later.  That is a phenomenal achievement, but the motivation was ultimately shallow and the effort could not be sustained for long after the race was “won”.  The last human presence on the Moon was in 1973 – 37 years ago.  We now do not have the wherewithal to repeat this feat.  As an aside, I wonder if that is the cause for the persistence of conspiracy theories that suggest the landings were a hoax.  Pick a technology, and insert it into this sentence: “37 years ago we had [insert technology here] that could do vastly more than they can do today”.  Any example is ridiculous, and virtually unbelievable.  “37 years ago we had phones/computers/cars vastly better than we have today”.  It doesn’t make sense, and there is a certain logic to squaring this circle by concluding that the landings never actually happened.
The problem this success causes us now is that it makes the solution seem so simple: persuade President, get cheque signed, job done.  Hooray!  Simpler, because the US is far richer now than it was in the 1960s (despite various recent economic incidents), and a much wider and deeper technological base is available.  But the space race was a product of the cold war, a very different geopolitical time.  Unless a new space race begins with China as the opponent, a single-government program is not going to get funded.  I have read many articles by frustrated space activists pointing out how much we spend on various fripperies or down-right wastes of money (pet food, ID cards, etc), and comparing this figure to how much we would need to spend to send people to Mars.  “Surely, if we spend this much money on that, we would be willing to spend it on sending people to Mars!”.  I agree, but it just washes over most people.  If that argument worked, it would have done so by now.  Nearly four decades of a theory failing should be enough to persuade us that it will never work, barring a huge change in global circumstances, none of which we should wish for.
What next?  International cooperation, that other stand-by of desperate space activists looking for a way to make the costs sound more palatable.  It is estimated that the ISS will cost 35 – 100 billion dollars (admittedly over a 30 year period).  So, we will end up spending at least twice as much on this as on a Mars Semi-Direct mission.  Of course, the ISS is not a shining example of the efficacy of international cooperation.  As with the single-government funding model discussed above, the fact that the option is not on the table now means that it isn’t going to happen.

As you can see, it sets the scene, but that is about it.  What I am starting to get interested in is how can non-government money fund space exploration?  Sub-orbital flight is on the cusp of being financially viable, but there is a big jump from there to orbit, and a bigger jump from orbit to beyond.  As well as developing this theme, I will also flesh out what I have written here soon.

Disproportional Representation update

I figured you were desperate for me to update the analysis in the last blogpost with the results of the 2010 election, so as it’s you…

This graph shows how the 2010 election results (large blobs) fit into the overall picture.

The next graph shows how the parties did in terms of how many seats they won per % of the vote.

Last time we observed that the winner had always come out on top by this measure.  This time round though, despite the Conservatives ending up as the largest party (albeit without a majority), Labour actually got more seats per % of their vote.  The unfortunate LibDems saw this measure decline for them this time round.  Further, the negative correlation I identified last time has done for them again this time.  Between 2005 and 2010, their share of the vote increased from 22% to 23%; however, they actually lost 5 seats, going from 62 to 57.  Apparently this has caused much upset to Billy Bragg.

Disproportional Representation

In case you didn’t know, there is a general election in the UK tomorrow.  The Liberal Democrats, the third party, have been agitating for a change in the electoral system for some time, because their representation in parliament is consistently much lower than it’s overall share of the vote would suggest is fair.

Without getting into whether or not a change in the voting system is a good idea (personally, I like the current first past the post system), let’s take a look at the figures.  I took the results in terms of seats gained and proportion of the vote won in all general elections between 1983 and 2005.  Early results for the LibDems are actually for the Liberal-SDP alliance, their precursor party.  Data points are colour-coded – blue for Conservative, red for Labour, and yellow for LibDems.

As you can see by the pattern of the data, the parties have to get to 15-20% before they get any seats at all.  Given that this is close to where the LibDems have polled this obviously puts them at a disadvantage.

Another way of showing this disadvantage is by calculating the number of seats won per percentage of the total vote achieved.  For example, if a party won 25% of the vote and got 250 seats, that would be 10 seats per %.

This chart shows two things.  First, it confirms the disadvantage that the LibDems have to fight against.  But more interestingly, at every election the winning party gets more seats relative to thr proportion of their vote than the opposition.  The Conservatives won the 1983 and 1987 elections by large margins, but also got more seats proportional to their actual vote.  The same can be said for Labour in 1997, 2001 and 2005.  The Conservatives very narrowly one 1992, where the proportions for Labour and the Conservatives are almost identical, with the Conservatives just shading it.  It also shows that the increase for Labour of seats in relation to their vote is more or less matched by the LibDems.

Finally, some stats.  The correlation between Conservative seats and vote share is 0.99; that for Labour is 0.96.  This shows an almost perfect positive correlation between vote achieved and seats gained (a perfect positive correlation is 1, a perfect negative correlation is -1, and no pattern at all is 0).  Weirdly, the LibDem correlation comes out as -0.27, that is the bigger share of the vote they get the fewer seats they win.  They really don’t do well under this system do they?  Having said that, looking at the first graph does not really show any such pattern for the LibDems, so it is probably a spurious result.

Risk – and splitting hairs

As society becomes more and more risk averse and “compliance” (i.e. box-ticking) based, what once was probably a sensible attempt at quantifying risk becomes increasingly silly.  Contaminated land – ground contaminated by former land uses and now presenting a risk to “receptors” (usually people or watercourses) – is one such area.

Old-school industry frequently left a polluting legacy – there were few if any rules on how you needed to control the polluting output from your processes.  It is not that uncommon to find significant pools of oil on or beneath the surface of derelict land that have persisted for decades.  It is undeniable that this can present a very serious health risk, therefore we are obliged to deal with the problem, and rightly so.

A large pool of oil (“free product” in the jargon) is clearly a problem which needs to be addressed.  But what about contamination that isn’t immediately visible?  Soil on an old industrial site can look like normal old soil but can actually be chock-full of nasties, you don’t need chunks of asbestos and pools of oil to present a risk.  In these circumstances, we will have needed to analyse the soil and determine the level of contaminants present.  But what do we compare it to?  What level denotes an unacceptable risk?

We can try and work that out.  We can make some assumptions, based on what we know of the chemical in question – how it behaves, how mobile it is, how quickly it breaks down.  But soil is highly variable, and differences in the properties of the soil can have a very large effect on the behaviour of the contamination.  Despite this, we can at least take measurements and determine how the contaminant ought to behave based on past experience and laboratory data.  Highly imperfect, but reasonably good.

The problems start to arrive when you consider how a human being using the site will be affected.  Will the site be a car park, with a small fringe of green around the outside?  If so, even quite high levels of contamination will probably not cause a risk as people tend not to spend much time on the small grass verges next to car parks.  But what if the site will become family homes with gardens?  This time, we need to be worrying about little children running around their gardens all summer, getting mucky and generally being exposed to contamination.  Clearly, the risk is greater.

But we still need to quantify this.  And once we have made the very sensible decision that we need to differentiate between people using a site as a car park and it being a family garden, we create a whole heap of trouble.  How do you QUANTIFY the difference in risk?  By making quantitative assumptions about behaviour.  You need to decide on some sensible assumptions for how often the typical person will be on the site, how long each visit will be, how much soil-derived dust they are likely to be inhaling (say the site is a sports field – the heavy breathing caused by exertion will increase this – but precisely how much?), how much dust they will “trackback” to their homes, and so on.

But making all these assumptions makes the model you have used highly specific.  Take the sports field for example.  A teacher regular taking PE lessons there could be at risk from contamination.  But how much is acceptable?  Part of answering that questions comes from making an assumption about how long they will be doing it for (as in years of their life).  To be on the safe side, most of these types of calculations assume that the adult will work at the site their whole working life.  But how long is that?!  I once had to rerun some calculations because it was decided that a teacher would be taking a one-year PGCE (teaching) course after they went to college, so their lifetime exposure to the playing field of death would be one year shorter.  When you get to that level of detailed assumption it becomes slightly absurd.  Unfortunately, this is the rod we make for our own backs when we take the perfectly sensible decision to distinguish between different types of risk.

So next time you read in the local paper that a site is “contaminated”, it may not be that simple.  Someone has made a very long list of assumptions that may or may not be an accurate reflection of what goes on.  And I haven’t even started on sampling error yet.

You don’t need to take a gap year…

…but you don’t need to go straight to university either.  What you need to do is get on with the next year of your life.

An article in the Daily Telegraph today entitled “Bridging the work experience gap” got me thinking about my attitude to gap years.  After college (study at 16-18, for my international readers) I intended to take a gap year, which soon turned into two.  By “take a gap year”, what I mean is I went to Vietnam for three months as a volunteer with the environmental NGO Frontier, doing environmental work.  My plan for the remaining nine months was to stay at home with my parents and have semi-regular work that would keep me in cider until I went to university, after which my student loan would be keeping me in cider (I was a late convert to beer).

However, I ended up getting a year-long contract as a chemistry analyst in a water company laboratory.  I only applied on the off-chance, it being the only job in the New Scientist that didn’t require a degree.  Somehow I got it, so I moved away from home and UEA kindly allowed me to defer taking up my place for another year.  It was awesome, and actually far more formative than my time abroad.  I moved in to a shared house in a new town, and started earning money and paying rent for the first time.

Was this a gap (two-)year?  It started out like that, with the standard extended overseas trip and an assured place at university.  Or was it just the next two years of my life, which happened not to be in formal education?  The idea of a gap-year implies that spending your entire time in formal education is the natural order of things and that doing something else, however positive, is a “gap” in the fabric of what you should be doing.  I don’t agree with this.  University isn’t for everybody, and university straight after college certainly isn’t.  I am a university person so I went to university.  But I am also someone who needs variety, so a two-year breather from formal education was just what I needed.  Some people should go straight to university, some never.  There are plenty of options, like delaying university, or studying part-time (the Open University is the biggest university in the UK!), or getting a job, or whatever.

So, don’t take a gap year, but do get on with the next year of your life.  Make it a good one.