Thursday 22 December 2011

Correlation of the year: Drinking encourages unsafe sex

If you thought the biggest science stories of 2011 concerned faster-than-light neutrinos, the Higgs Boson or the discovery of ever more exoplanets, you would be wrong.

Researchers at the Centre for Addiction and Mental Health in Toronto, Canada have performed a meta-analysis of 12 previously conducted experiments and found that drinking alcohol makes people want to have unsafe sex. Their paper, Alcohol consumption and the intention to engage in unprotected sex: systematic review and meta-analysis of experimental studies, published in the journal Addiction, showed that alcohol consumption directly impacts a person’s intention to have unsafe sex. That is, the more you drink, the stronger becomes your intention to engage in unsafe sex.

Well I never. Generations of children owe their lives to this phenomenon!

The researchers were actually testing something a little more subtle than this appears. They wanted to test whether alcohol consumption influenced the contraction of HIV via unsafe sex, or whether certain personality traits, such as a disposition to risky behaviour, would lead to both alcohol use and unsafe sex - that is, if the unsafe sex would have happened anyway, regardless of alcohol.

They found that the more people drank, the worse the decisions they made. An increase in blood alcohol level of 0.1 mg/mL led to a 5% increase in the likelihood of unprotected sex.

"Drinking has a causal effect on the likelihood to engage in unsafe sex, and thus should be included as a major factor in preventive efforts for HIV," said principal investigator Juergen Rehm in a statement. "This result also helps explain why people at risk often show this behaviour despite better knowledge: alcohol is influencing their decision processes."

So remember this over the holidays at your work Christmas parties when your boss starts to look good after 8 beers. And at your family gatherings, your second cousin is still related....

Rehm, J., Shield, K., Joharchi, N., & Shuper, P. (2012). Alcohol consumption and the intention to engage in unprotected sex: systematic review and meta-analysis of experimental studies Addiction, 107 (1), 51-59 DOI: 10.1111/j.1360-0443.2011.03621.x

Friday 25 November 2011

My favourite Sesame Street science videos

I'm stranded at Adelaide airport with my flight delayed for four hours, so what better way to get back onto the blog than by sharing my favourite Sesame Street science videos (Sesame Street having recently resumed it's exalted position in my life). The other day they were using the scientific method to deconstruct fairy tales - how would you tell the difference between the Big Bad Wolf and Grandma? Those videos aren't up online yet, but let's kick this off with comedian Craig Ferguson helping to define the word "experiment".

Here's Elmo and a Justin Bieber look-alike singing "Measure, Yeah, Measure," to the tune of Bieber's song "Never Say Never." I like his hair flicks. Elmo measured it, yo.

This is pretty cool, a Cookie Monster interactive video teaching us about experiments and things that float:

In this one, Emma Stone balances stuff on her head:

Here's Ernie showing all the curiosity of a good scientist:

And this is not sciencey, but it's the best Sesame Street video. Cutest thing you will ever see!

Friday 29 July 2011

The 27 Club

Brian Jones, Jimi Hendrix, Janis Joplin, Jim Morrison, Kurt Cobain, and this week tragically Amy Winehouse, all died at the age of 27. This coincidence has spawned the notion of the 27 Club - a club whose members are influential musicians who died at the age of 27. But is there anything statistically significant about this club? Should musicians fear turning 27?

There are a few things that we should note before starting this investigation:
  1. It's quite clear that it is not true to say that more influential musicians die at the age of 27 than at any other age. If this were true, musicians would be dying all the time, and the facts that our radios are filled with golden oldies and John Farnham keeps touring are testament to this. 
  2. We will never find enough data to fully test out any theory we come up with. For example, what defines an "influential" musician? One approach might be to scour wikipedia and find the death dates of every artist who had a top ten hit in the last 50 years. I leave this as an exercise for the reader.
What we will do for this article is redefine the club to be for musicians who have died through misadventures with drugs. And what do you know, wikipedia has an article dedicated to just this topic - a list of celebrities who had drug-related deaths. Looking at just the 100 musicians in the list, we get the following distribution for lifespans of musicians who died through drug misadventure.

This distribution has an average of 36, a median of 34 and a mode of 28. All pretty close to 27. Maybe there's more to this than we thought. This can be compared to Australian Bureau of Statistics data for Australian males between 2007 and 2009. It's clear that musicians who have drug-related deaths are dying at a much younger age than Australian males. Note the caveat here, the musicians aren't dying of old age - these are only musicians who have drug-related deaths.

It's easy enough to come up with a theory for this. Musicians - indeed society at large - are most likely to start being exposed to drugs at the age of 20. In any case, before this time there aren't many musicians popular enough to have a wikipedia page or a public influence strong enough to be accepted into the 27-Club. The number of deaths seems to drop off after about the age of 40, but this is not because they are all becoming family oriented and leading a clean life. The number drops because there are less musicians alive at 40 to die. This is the same explanation for why less people in the general population die at the age of 95 than do at 80 - not that many people live long enough to die at 95.

The following chart displays the probability of dying within the next five years given that you have survived to now. For example, if you are currently in the 60-64 year age range, this chart shows the probability of dying in the 65-69 year age range. For musicians who have drug-related deaths, between the ages of 20 and 65, the chance of dying in the next 5 years is between 25-50%. Within the noise of the small sample set, its about the same for each 5 year category between 20 and 65, perhaps increasing slightly with age. This suggests that for influential musicians, if they are going to die through drug use, they have roughly the same chance of dying within the next 5 years no matter how old they currently are, perhaps a little higher if they're older. The probability of death doesn't peak at 27, and conversely, just because you have survived till now doesn't mean you have a greater chance of surviving the next five years. This is similar to the distribution of cricket batting scores, for those interested.

The peak at 25-29 in the previous chart occurs only because the musicians have not died before that age and suggests there is nothing supernatural about the number 27 (despite the curse of 27). Note that for Australian males, the data stops at 100 so the 100+ bar represents dying above this age. For the musicians, the data stops at 70-74, hence its peak at 100%.

Note again that this analysis is for musicians who die drug related deaths. It doesn't suggest that musicians have shorter lifespans than the average Australian male - it does however suggest that musicians who die via drugs have shorter lifespans. This could be because if you are going to die a drug-related death you are likely to die young because taking drugs is a risky endeavour, or it could be because by the age of 75 you have probably stopped doing drugs and so your death doesn't appear in the chart.

So is there anything to the 27 club? Not really. We've shown (albeit with just one rather incomplete article on wikipedia) there is nothing magical about the age of 27 - indeed 28 seems more interesting - and the peak in drug-related deaths around this age is quite predictable. Far more musicians die at an older age of other causes just like the rest of us, and somehow Keith Richards is still alive. The club exists because humans like to associate meaning to patterns. We're very good at pattern recognition. Our ability to associate the seasons with animal migrations, and the stars in the sky with when to plant vegetables, gave us an advantage throughout evolution. However, false pattern recognition doesn't get us killed and so we often spot patterns where they don't exist - for example, we see faces in the World Trade Center disaster, or the Virgin Mary at the beach. Some even believe that because of this, we have created religion to explain patterns we can't explain.

A nod here to the like-minded Bespoke Blog and its article Morbid Statistics & The 27 Club which I found quite coincidentally as I was finishing up this article. 

Sunday 17 July 2011

Ep 143: TedxSydney - Bryan Gaensler

TED is a US based not-for-profit enterprise devoted to the propagation of Ideas Worth Spreading. TED started out in 1984 as a conference bringing together people from three worlds: Technology, Entertainment and Design. TedxSydney was a Sydney-based TED event, bringing people together to share a TED-like experience. I ducked out to Carriage Works to catch some of the event, and you can see all the talks over at the TedxSydney youtube channel. Many of these talks were science based, so I'm going to put up some of my favourites over the next few posts.

The following video is from Bryan Gaensler, former Young Australian of the Year, NASA Hubble Fellow and Harvard professor, Australian Laureate Fellow at The University of Sydney, and Director of the Centre of Excellence for All-sky Astrophysics. His talk was entitled A new way of looking at the sky.

Ted Copyright
TEDTalks are distributed under a Creative Commons (CC) license. Anyone is free to download the videos from; share them with friends; republish or embed them on their website or blog. But this use must be made within the terms of the CC license "Attribution -- NonCommercial -- NonDerivative."

Monday 13 June 2011

Ep 142: Beyond Zero Emissions

Beyond Zero Emissions is a not-for-profit, volunteer run organisation whose core goal is to develop blueprints for the implementation of climate change solutions. In partnership with the University of Melbourne's Energy Research Institute, BZE are undertaking the Zero Carbon Australia 2020 Project, which puts together fully costed transition plans for getting Australia to zero emissions in ten years using commercially available technology.

Last year I attended their launch event for the Zero Carbon Australia Stationary Energy Plan which goes into detail about how Australia can reach 100% renewable energy within a decade. Speakers at the launch included former NSW premier Bob Carr, member for Wentworth Malcolm Turnbull, Greens Senator Scott Ludlam and Matthew Wright, Executive Director of BZE. The event was hosted by journalist Quentin Dempster.

In this podcast, with permission from Matthew Wright, I bring you Matthew's speech at this launch which details the science behind their proposal. I also chatted to BZE volunteer Petra Liverani at the recent Say yes to a price on carbon pollution rally in Sydney.

Click play below or listen to this show here:

If you'd like to hear what Turnbull, Carr and Ludlam had to say, check out the full video of the launch below, reproduced here with permission.

Wednesday 8 June 2011

Total lunar eclipse across Australia (or what is a syzygy)

Today I learnt a new word.


A syzygy is a straight line configuration of three celestial bodies (such as the Earth, Sun, and Moon), and on Thursday 16 June, if you can get yourself up before dawn, you will witness a syzygy - in this case a total lunar eclipse - above the western horizon as the Moon passes through Earth’s shadow. This syzygy ends at sunrise in all states but Western Australia. It has been something of a star and planet watcher's dream recently, with four planets having lined up in the sky during May.

The eclipse begins at 3:25am AEST and enters its darkest phase at 05:22am AEST when the transformation to a blood-red Moon should begin. The colour of the eclipse depends on the amount of dust in the Earth's atmosphere. The red colour comes about because sunlight reaching the Moon passes through the Earth’s atmosphere where it is scattered. Shorter wavelengths (blue) are scattered more by  air molecules and dust particles than longer wavelengths (red), and so by the time the light has passed through the atmosphere, the light is mainly red. In extra-solar planets - planets in other solar systems - lunar eclipses can be used to determine the content of the planetary atmosphere. You might remember back to 2009 when Sydney was covered in dust and turned red to gauge a feeling for what the colour could be like - check out that article for a fuller description of the physics involved as it is similar.

If you are keen enough to not only get out of bed but to leave your house, Sydney Observatory is hosting a special breakfast viewing which includes tea, coffee, croissants and “blood-red” jam. Book at the Sydney Observatory website.

This material came from the Sydney Observatory.

Wednesday 1 June 2011

There is more kicking in Union than League (and other misconceptions)

If you listened to the crowd at a Waratahs (Rugby Union) game, apart from wondering which side the so-called fans were barracking for, you'd think that the Waratahs kicked the ball too much. If you have ever listened to a Rugby League fan wax lyrical about how Union teams keep kicking the ball away and how League teams know how to cross the try line, you might start to become convinced that Union teams really do kick too much. But as we like to do here, let's put these popular notions to the test. Is there really more kicking in Union than League?

The question originated at my work, where most Mondays - indeed most days of the week - we debate the relative merits of the two rugby codes. So if for no other reason than to prove my own hunch, I compiled the data for the current season of the Australian National Rugby League (after round 12) and the three nation Super Rugby (after round 15) tournaments. The following chart shows the distribution of the number of times each game a team kicks the ball.

Kicks per team in a game of rugby and league
We can conclude:
  • This year in the NRL, each team averages 19.05 kicks per game. In Super Rugby, each team averages 19.07 kicks per game - there is essentially no difference between the average number of kicks in a Union game and a League game in 2011. The difference of 0.02 is well below what we need for statistical significance;
  • Both sets of data look pretty-much bell shaped - that is, they are close to normal distributions (probably as a result of the Central Limit Theorem). The League distribution is thin and tall - there is only a small distribution about the mean (standard deviation of 3.8) - whilst the Union distribution is fatter (standard deviation of 6.2). This suggests that in a League game, most of the time teams will kick somewhere near this average number of times (19), whilst in a Union game you are more likely to see a game with not many kicks or a game with a lot of kicks. This is a result of the fact that in League, after the 5th tackle, you don't have many other options but to kick, whilst in Union, with an unlimited tackle count and continual contest for the ball, you have more options for when and how often you wish to kick.
  • The notion that it's the boring teams that kick too much take another hit when you look at the teams who actually do kick the most. The Reds, lauded this year for playing running rugby, are top of the kick table, whilst the Brumbies, who can't beat anyone, are stuck at the bottom of the kick and Super Rugby tables. In the NRL, the top three kicking teams are 3 of the top teams in the competition. Check out Green and Gold Rugby for more on the Super Rugby kicking stats.

    Super 15NRL
    Stormers20.1Sea Eagles20.2
    Wests Tigers15.6
  • I find it fascinating that the averages come out so close. It's over 100 years since the codes split from their common ancestor, and despite numerous law changes and evolutionary paths, teams in League and Union seem to want to hold onto the ball, on average, for about the same amount of time. In league, you are limited to 6 tackles, so could it be that the law-makers of League, when devising the 6 tackle rule, knew instinctively that this is the right balance of attack and defence? Does this balance give the players just the right amount of rest during a game? Or is it all a coincidence?
And while we're on the topic of maths and sport, it's important when doing statistical analysis on sport that you analyse the right thing and take note of statistical significance. Despite the popular saying, statistics don't lie, but poor use and interpretation of them does. I think this comic from xkcd sums up how I feel when I listen to ex-professional sportsmen commentating on sport...

With regards to cricket, we have shown here on the blog that a batsman's cricketing scores over his career fit the exponential distribution very well, suggesting that many notions of cricketing form, and discussions of it, are quite troublesome - that is, it's not form creating the fluctuations in a batsman's career, but the very nature of the game itself. Deep.

Kicking images courtesy State of Union address - Tom Bradshaw's rugby blog. Yes I support the Waratahs and believe wholeheartedly that Rugby Union is a much better game than League. And unlike other Waratahs fans, I think they're actually pretty good!

Sunday 15 May 2011

How the planet alignment worked (and why astrology does not)

Did you get up at 5am and brave the cold to see the planets align? If you had, you would have seen something like this. Venus and Jupiter were very bright, Mercury was fainter and eventually fell behind some clouds, and I couldn't see Mars at all with the naked eye. It was only with this long exposure shot that I could see what I think to be Mars. I've put up a bunch of photos on flickr.

All four planets over Canterbury, Sydney

The reason we were treated to this early morning light show was because of a rare alignment of the planets. It's not rare due to being unexpected - it's completely predictable - it just doesn't happen all that often. The next time these four planets will get together will be in 2056.

The following images have been made using the excellent Solar System Live by John Walker. The site shows the positions of the planets around the Sun, and in the sky, either live or at a time of your choosing. On May 13, the four inner planets were all in a straight line and from Earth you could view the other three clumped together in the sky. The images show the solar system from above, with the orbits spaced equally for ease of viewing. From this viewpoint, the Earth spins counter-clockwise on its axis, and counter-clockwise around the Sun. The alignment of planets is not seen until just before dawn, however as the Earth continues to rotate and the Sun comes into view, the light from the Sun becomes too strong to see the planets (you rarely see stars or planets during the day). Unseen, they continue to track overhead during the day. By the end of May, as the various planets move at different orbital speeds around the Sun (a year is different on each planet), they will be in different parts of the sky and the light show over.

Inner Planets

If you take a closer look at the figure below, you'll notice that besides the aligned planets, there are actually six planets visible in the dawn sky - all planets except Saturn can be spotted if you find a dark enough area, although you'll need binoculars to see Uranus and Neptune. Even Pluto, if you still maintain it to be a planet, might be found with a small telescope - the Solar System live site still has Pluto in its diagrams. A crescent Moon will reappear near the end of May to add to the scenery.

All planet line up

For more information, this video from ScienceCasts gives a great overview of the phenomenon, showing how the planets move in the sky throughout May. It's also a geometry lesson before breakfast. Check out for more.

The alignment of the planets has various meanings in astrology and some astrologists maintain that there is science behind their beliefs, often claiming the precise positioning of the planets and stars at your birth effects you through gravity. Whilst these effects may be small, some claim they're enough to influence your developing brain and therefore your personality. Let's test the theory. To find out the gravitational force between two masses, we use Newton's law of universal gravitation:

  • F is the force between the masses,
  • G is the gravitational constant,
  • m1 is the first mass,
  • m2 is the second mass, and
  • r is the distance between the masses.
We can use this to examine the gravitational force between a one kilogram mass on the surface of the Earth and the distant planets. The distances the planets were from Earth on May 13 were obtained from Solar System Live, and their masses from NASA. I've also included the gravitational effect of my car if you were standing 50 cm from it.
As you can see, the gravitational effect of my 1.5 tonne car is greater than all the planets put together.

It is also important to note that on May 13, the pull of the Moon on our 1kg object was 199 times bigger than that of Jupiter's at the Earth's surface. The Sun's pull was 178 times bigger than the Moon's, and the pull of the Earth itself was 1656 times bigger than the Sun's. Essentially, the pull of the planets on an object at the Earth's surface is negligible. The calculations can be explored in this spreadsheet. Read more over at Bad Astronomy debunking the claims of astronomy, especially with regards to gravity and the tides.

So, don't blame Jupiter if luck doesn't favour you this month - blame my car. Oh Marc, that is such a Taurian thing to say...

Wednesday 11 May 2011

Four planets align over Sydney at dawn Friday 13 May

When the moon is in the Seventh House
And Jupiter aligns with Mars
Then peace will guide the planets
And love will steer the stars.

The age of Aquarius has arrived! Well, it will, this Friday 13th May.

In a rare planetary event, Mercury, Venus, Mars and Jupiter, will appear together (within around 2 degrees of each other) in the eastern sky just before dawn this Friday. The event will be particularly spectacular for Sydneysiders. From 5am, the four planets will be clearly seen just above the horizon in the east. The brightest planet will be Venus sitting in the middle of the group. Just above and to the left of Venus and almost as bright is Jupiter. To the right of Jupiter and slightly fainter will be Mercury. Sitting below these three planets and fainter again will be Mars. The four planets are quite bright, so if you are up early enough, you will see them over city lights.

If you have been up early recently (I had the pleasure of a 5am start today for work...) you will have already noticed Venus and Jupiter together. The last time these four planets came together was in 1910, but the planets were too close to the Sun to observe. The next close grouping of these planets will not be until 2056.

“The close grouping of these particular four planets only happens every 50 to 100 years. We are hoping for a clear autumn morning for this unique sight in the southern sky,” said Sydney Observatory’s acting curator, Andrew Jacob. The event will be visible to the naked eye and Sydney Observatory is holding a breakfast viewing. If you are interested in getting along, there is more information at, and check out the Observatory's blog.

The last cool astrological event that we've seen in Sydney was back in 2008 when the Moon, Venus and Jupiter aligned to form a smiley face in the sky. I was a bit late for the happy face but managed to capture a grainy celestial sad face. Time will tell whether I manage to drag myself out of bed at 5am for this latest viewing - with a new born bub, you never know...

Addendum: Here's an explanation of how the alignment gave such a great view from Earth, and why my car is more likely to influence your personality - astrologically speaking - than this rare alignment.

Friday 22 April 2011

Ep 141: Science of Superheroes - Harry Potter

And we're back! It's been a while, but finally it's time for another podcast, so we've made it a long one. Take this episode on a long train ride or car trip, as Dr Boob and I explore the science of the spells of Harry Potter.

Attempting to find scientific and engineering solutions to Harry Potter spells is probably the most difficult task we have set ourselves yet, so we would be very interested to hear how you would made the Harry Potter spells a reality. The spells dealt with in this episode are:
  1. Lumos - Producing light from the end of a wand (A voice activated torch seems a logical solution),
  2. Aguamenti - Shooting water from the end of the wand,
  3. Alohomora - Picking a lock at a distance,
  4. Expecto Patronum - Protection against evil dementors in the form of some virtual creature,
  5. Sectumsempra - Slicing your opponent open,
  6. Aparecium - Reading invisible ink,
  7. Accio - Summoning things to you,
  8. Expelliarmus - Disarming your opposition of their wand,
  9. Confundo - Confusing the victim,
  10. Stupefy - Stunning the victim,
  11. Invisibility cloak - Covering yourself in a cloak to make yourself invisible,
  12. Imperio - Forcing your victims to obey your commands,
  13. Obliviate - Erasing the memories of the victim,
  14. Legilimens - Telepathy.
Although some of these are quite clearly impossible at the moment, in every case we have come up with a scientific or engineering solution to take us at least part of the way there. Listen in to find out what we came up with, and please write in and let us know where we have gone wrong or what you would do.

Click play below or listen to this show here.

  1. Santos, V., Paula, W., & Kalapothakis, E. (2009). Influence of the luminol chemiluminescence reaction on the confirmatory tests for the detection and characterization of bloodstains in forensic analysis Forensic Science International: Genetics Supplement Series, 2 (1), 196-197 DOI: 10.1016/j.fsigss.2009.09.008
  2. A.J. Barnier and D.A. Oakley (2009). Hypnosis and Suggestion Encyclopedia of Consciousness DOI: 10.1016/B978-012373873-8.00038-4
  3. T.C. Jerram (1982). Hypnotics and sedatives Side Effects of Drugs Annual DOI: 10.1016/S0378-6080(82)80009-3
  4. Wood, B. (2009). Metamaterials and invisibility Comptes Rendus Physique, 10 (5), 379-390 DOI: 10.1016/j.crhy.2009.01.002

Tuesday 5 April 2011

Are NSW players over-represented in the Australian cricket team?

In every sports competition in the world, fans of one team will claim another team gets more favourable treatment than their own, whether it’s selection in representative teams, concessions regarding player salaries or favourable refereeing decisions. Cricket in Australia is no different. The dawn of summer is almost inevitably accompanied by bleating, generally from Victorian fans, about how players from New South Wales are more likely to be selected in the national team than players from other states. This opinion found a voice in David Hookes, who claimed:

"When they give out the baggy blue cap in New South Wales, they give you a baggy green one in a brown paper bag as well to save making two presentations."

It’s about time we put this idea to the test. Since the 1977/78 season, all 6 Australian states have played in the Sheffield Shield, Australia’s domestic first-class cricket competition. Since 1982/83, the season has culminated in a grand final (previous to this the winner was determined league style by whoever won the most throughout the season). I will use data from 1982/83 till now for consistency and so that all states are represented. The following table shows the players who have debuted for Australia since the start of the 1982/83 season, the state they were playing for at the time of their debut, and the number of Tests they played throughout their career.

Carl Rackemann 1982–9112QldMatthew Elliott 1996–200421Vic
Kepler Wessels 1982–8524QldMichael Kasprowicz 1996–200638Qld
Tom Hogan 1983–847WAJason Gillespie 1996–200671SA
Roger Woolley 1983–842TasAndy Bichel 1997–200319Qld
Wayne B. Phillips 1983–8627SAShaun Young 19971Tas
John Maguire 1983–843QldSimon Cook 19972NSW
Greg Matthews 1983–9333NSWStuart MacGill 1998–200844NSW
Steve Smith 19843NSWGavin Robertson 19984NSW
Dean Jones 1984–9252VicPaul Wilson 19981SA
David Boon 1984–96107TasAdam Dale 1998–992Qld
Bob Holland 1984–8611NSWDarren Lehmann 1998–200427SA
Murray Bennett 1984–853NSWColin Miller 1998–200118Tas
Craig McDermott 1984–9671QldMatthew Nicholson 19981WA
Simon O'Donnell 19856VicAdam Gilchrist 1999–200896WA
Dave Gilbert 1985–869NSWScott Muller 19992Qld
Robbie Kerr 19852QldBrett Lee 1999–201076NSW
Merv Hughes 1985–9453VicSimon Katich 2001–56WA
Geoff Marsh 1985–9250WAMartin Love 2002–035Qld
Bruce Reid 1985–9227WABrad Williams 2003–044WA
Steve Waugh 1985–2004168NSWNathan Bracken 2003–055NSW
Simon Davis 19861VicAndrew Symonds 2004–0926Qld
Tim Zoehrer 1986–8710WAMichael Clarke 2004–67NSW
Chris Matthews 1986–883WANathan Hauritz 2004–17Qld
Greg Dyer 1986–886NSWShane Watson 2005–25Qld
Peter Taylor 1987–9113NSWShaun Tait 2005–083SA
Mike Veletta 1987–908WAMichael Hussey 2005–57WA
Tim May 1987–9524SABrad Hodge 2005-086Vic
Tony Dodemaide 1987–9210VicPhil Jaques 2005–0811NSW
Ian Healy 1988–99119QldStuart Clark 2006–0924NSW
Trevor Hohns 19897QldDan Cullen 20061SA
Mark Taylor 1989–99104NSWMitchell Johnson 2007–40Qld
Greg Campbell 1989–904TasChris Rogers 20081WA
Tom Moody 1989–928WABrad Haddin 2008–30NSW
Mark Waugh 1991–2002128NSWBeau Casson 20081NSW
Shane Warne 1992–2007145VicCameron White 2008–094Vic
Wayne N. Phillips 19921VicPeter Siddle 2008–20Vic
Paul Reiffel 1992–9835VicJason Krejza 20082Tas
Damien Martyn 1992–200667WADoug Bollinger 2009–12NSW
Justin Langer 1993–2007105WAAndrew McDonald 20094Vic
Jo Angel 1993–954WABen Hilfenhaus 2009–15Tas
Michael Slater 1993–200174NSWPhillip Hughes 2009–8NSW
Brendon Julian 1993–957WAMarcus North 2009–21WA
Glenn McGrath 1993–2007124NSWBryce McGain 20091Vic
Matthew Hayden 1994–2009103QldGraham Manou 20091SA
Michael Bevan 1994–9818NSWClint McKay 20091Vic
Damien Fleming 1994–200120VicRyan Harris 2010–4SA
Phil Emery 19941NSWTim Paine 20104Tas
Greg Blewett 1995–200046SASteven Smith 2010–3NSW
Peter McIntyre 1995–962SAPeter George 2010–1SA
Stuart Law 19951QldXavier Doherty 20102Tas
Ricky Ponting 1995–151TasMichael Beer 2011–1WA
Brad Hogg 1996–20087WAUsman Khawaja 2011–1NSW

Of the 104 players who debuted after 1982/83, 28 were playing for NSW when they were first picked for Australia (27% of the new players).


Clearly NSW players have played more Tests. But is this unreasonable? There are two measures we can look at here. Sheffield Shield results and state populations. The following shows the results of the Shield since 1982/83.

Season Winner Second Third Fourth Fifth SixthSeason Winner Second Third Fourth Fifth Sixth
1982–83 NSWWASATasQldVic1997–98 WATasQldNSWVicSA
1983–84 WAQldTasNSWSAVic1998–99 WAQldVicSATasNSW
1984–85 NSWQldSAWAVicTas1999-00 QldVicWASATasNSW
1985–86 NSWQldVicWASATas2000–01 QldVicNSWTasWASA
1986–87 WAVicQldSANSWTas2001–02 QldTasWASAVicNSW
1987–88 WAQldNSWVicSATas2002–03 NSWQldVicSAWATas
1988–89 WASAQldNSWTasVic2003–04 VicQldTasWANSWSA
1989–90 NSWQldSATasWAVic2004–05 NSWQldWAVicSATas
1990–91 VicNSWQldWASATas2005–06 QldVicSATasWANSW
1991–92 WANSWVicQldSATas2006–07 TasNSWVicQldWASA
1992–93 NSWQldWASATasVic2007–08 NSWVicWATasSAQld
1993–94 NSWTasWAVicSAQld2008–09 VicQldSATasWANSW
1994–95 QldSAVicWANSWTas2009–10 VicQldNSWWATasSA
1995–96 SAWAQldTasNSWVic2001–11 TasNSWQldWAVicSA
1996–97 QldWANSWTasVicSA

NSW has won 9 Shields, ahead of WA’s 7. If you look at the percentage of Shield wins per state and compare this to the number of players picked for Australia from that state, you will notice that these results are remarkably similar. Is it any surprise that the most successful team over this time has more players picked for representative honours? If you look at all the Tests played since 82/83, 34% of the Test positions up for grabs were occupied by NSW players, and the order of states is exactly the same as the order for number of Shield wins. This is strong evidence that rather than a selection bias, players are being picked either because they are the best players or because they have been a part of successful teams.

PlayersTestsShield wins

The second way to look at this is by state population. I don’t particularly like this method because sportsmen, especially in this professional age, move teams for many reasons, including for better opportunities and more pay, and don’t necessarily play for the state of their birth. The most populous state is not necessarily going to have the best team. But because this is often the first measure people look to when analysing team results (for example, Olympic results), and because arguably a larger population means a bigger economy and therefore more money flowing through the team, we shall include some analysis. Since 1982, NSW (+ACT) has averaged 36% of the total population of the states (excluding Northern Territory). Again, this matches quite closely the number of players picked for Australia – indeed, you might argue that more players from NSW should have been picked. It would be by this measure that Victorians may claim some bias.

PopulationShield Wins
NSW + ACT36%31%

Finally, let’s look at the one-test wonders – the players who only played one test.

One Test wonders

Victoria and SA share this honour with 4 one-test wonders – and this is possibly why David Hookes, of SA stock and coach of Victoria after his retirement, was cranky. In the case of SA, this is a third of their players who have made their debut since 1982/83 – indeed, 7 of their 12 Test players did not play more than 4 Tests. Tasmanian players also fair poorly in this regard, with 6 of their 10 players playing no more than 4 Tests – Tasmanian results are severely skewed by Ponting’s 151 and Boon’s 107 Tests.

No matter what state a Test player is from, he has roughly the same chance of playing 15 or more Tests. Thus the data does not support the idea that selectors are more likely to stick with NSW players through a patch of poor form.

Percentage of state Test players (15+ Tests)

I would be interested to hear your thoughts regarding this – I know it can stir some passions. But the data would suggest that there is no unfair bias towards NSW.

Further thoughts:
  • I have made no attempt to look at players moving state during their careers. Simon Katich, for instance, had a career revival when playing for NSW, even though he was originally picked for Australia when playing for WA. Nathan Hauritz similarly had his fortunes revived when playing for NSW, even though he debuted when playing for Queensland. There are also many examples of this working the other way – Jason Krejza moved to Tasmania, and Adam Gilchrist to WA, both from NSW and then made their debut. Even Don Bradman first played for NSW before an ongoing career with SA.
  • You could do the same analysis if you have time and patience on your hands for one-day and Twenty20 cricket.
  • It was quite difficult in some cases to track which state a player was playing for when they made their Australian debut, especially if they moved state soon after. I have put the data here (some of the array formulae don't work in Google docs, and I have stripped out the macros, but you can redo them). If I have made a mistake, let me know!

Monday 14 February 2011

Search Traffic in Egypt

The Egyptian Revolution of 2011 was a series of street demonstrations that demanded the overthrow of the Egyptian President Hosni Mubarak. One of the government retaliations to the protests was to shut down the Internet. Imagine you're a youth in Egypt and all of a sudden you don't have access to the Internet with its social networks, games and unlimited porn. You'd protest too! Great strategy guys...

Here is the Google search traffic in Egypt normalised against world-wide Internet traffic, created through Google Transparency Report. As you can see, it took a little less than a week for the government to realise their folly.

Wednesday 9 February 2011

Science events for February, and a little bit of Valentine love

February is a big month for science, and a big month for love. Here are a couple of events that caught my eye.


The Global Google Science Fair is an online science competition open to all students aged 13 to 18 from around the world. Unfortunately, I'm now way too old to enter, but were I still at school, this would be a fantastic opportunity to have some fun with science and technology. Scientific American, Lego, National Geographic and CERN are partners in the science fair, whose winner will receive a $50,000 scholarship, a 10-day trip to the Galápagos Islands and a virtual internship at Lego or a three-day site visit to CERN, Google or Scientific American.

The idea behind the show is that it is a chance for participants to showcase their ideas and experiments. Entrants are required to submit their work either as a video or slide show on their website (using Google products of course), and the works can fall into the following categories:
  1. Computer Science & Math
  2. Earth & Environmental Sciences
  3. Behavioral & Social Sciences
  4. Flora & Fauna
  5. Energy & Space
  6. Inventions & Innovation
  7. Physics
  8. Biology
  9. Chemistry
  10. Food Science
  11. Electricity & Electronics
Check out the Official Rules carefully and watch the video below for an introduction:


The Powerhouse Museum is opening three new exhibitions in February and March 2011. The exhibitions, Engineering Excellence (open now), designTECH (opens 19 February) and Student Fashion (opens 12 March), showcase emerging innovators and designers in New South Wales.

Six local and international contemporary engineering projects that recently received industry awards are on display in Engineering Excellence. They include a spectacular, fully-glazed building, design-engineered to a complex geometry with a unique waste collection and removal system, in one of the Middle East’s biggest developments in Abu Dhabi; an articulated head featuring a robotic arm attached to the image of a human face that ‘chats’ with the visitor; an internet laboratory for engineering students living and working remotely; new technology for producing renewable energy for electricity generators; a new optical device for microscopes that lights up hard-to-detect bacteria; and a new track safety system for a 350km per hour China Fast Train project.

Furniture, fashion, technology and leisure products are among more than twenty HSC student works in designTECH.  Humanitarian concerns such as the 2010 Haiti earthquake and the use of child labour in manufacturing, and health and safety issues such as 2009 swine flu and pool drownings were just a few of the motivating factors that inspired the student works. Some of the unique ideas on show include a homeless shelter designed for natural disasters; a brake device for runaway prams; a supermarket trolley aid for the elderly; a learner driver log iPhone app; and a pool fence alarm system.

Adelaide (and the world):

We've blogged and podcast about the science of love and sex many times, and with Valentine's Day coming up, the Royal Institute in Adelaide is putting on a special love themed event, Seven Deadly Sins: 'Lust' - Is Love Blind? Running the show will be Rob Brooks, who we spoke to at the end of last year in Ep 136: Sexual Selection about how evolution not only favours animals with the ability to survive, but also those who are attractive to the opposite sex and therefore more likely to reproduce. If you can't make the Adelaide event, it will streamed live on their site.

While we're on the topic of love and Valentine's Day, if you are looking to get the attention of that one special person, check out the Science of Speed-Dating, and our Scientific Dating Tips. If you are lucky enough to be waist deep in romance, then check out the reasons why we fall in love, and how love is simply a chemical process in the brain. And if you simply just want to get lucky, then check out:
If you think this whole love and sex thing is just one big joke, then perhaps the idea that those who are more sexually appealing may be dumber might be up your alley. Or talk sex over a beer with the Beer Drinking Scientists.

Tuesday 25 January 2011

Ep 140: The Redback Spider invasion of New Zealand

Research published in Biological Invasions shows that Australian redback spiders are invading New Zealand and could become established in many urban areas around major ports.

The paper, The invasive Australian redback spider, Latrodectus hasseltii Thorell 1870 (Araneae: Theridiidae): current and potential distributions, and likely impacts, details recorded sightings of redback spiders in New Zealand, then used biological and climatic information to reveal where redbacks could establish. Warm, dry conditions in some eastern areas of New Zealand are suitable for redback spiders to become established, and they are likely to spread further as they are surviving in places with relatively high rainfall. Urban areas, for example, provide shelter from the rain. The spread of redbacks is likely to have arisen from the establishment of new invasions through New Zealand's ports.

There is genetic evidence that redbacks have interbred with the protected, endemic katipo and there is a danger that redbacks could competitively displace katipo or cause extinction by interbreeding. Redbacks are also a public health issue as they have the potential to become established in areas close to urban populations. Successful border control already produces regular interceptions of the redback as well the invasive brown widow and the western black widow. Both these species are related to the redback and have similar habitat and climate requirements.

I spoke to lead researcher Dr Cor Vink about this work and how they are developing new approaches and tools to ensure harmful organisms are kept out of New Zealand.

Click play below or listen to this show here.

Cor J. Vink, José G. B. Derraik, Craig B. Phillips, & Phil J. Sirvid (2010). The invasive Australian redback spider, Latrodectus hasseltii Thorell 1870 (Araneae: Theridiidae): current and potential distributions, and likely impacts. Biological Invasions

Sunday 16 January 2011

And introducing....

Hope you've all had a wonderful Christmas and New Year. We'd like to introduce you to our little bloke, Luka, born on the 29th December 2010. Everyone here is happy and healthy, if a little tired. I'll get back to the blogging and podcasting soon...