Posts filed under Research (206)

This isn’t in the NZ media yet, but it will probably turn up soon.  A second CERN experiment, ICARUS,  has repeated the measurement of neutrino speed made by the famous OPERA experiment: the same neutrino source, the same distance, but different measurement equipment.   And the neutrinos arrived on-time, not 60ns early. Since the OPERA results violate relativity  and have other practical and theoretical problems , it’s not that hard to decide which set of numbers to believe.

As Prof. Matt Strassler says

This is the way it works in science all the time. A first experiment makes a claim that they see a striking and surprising effect. A second experiment tries to verify the effect and instead shows no sign of it. It’s commonplace. Research at the forefront of knowledge is much more difficult than people often realize, and mistakes and flukes happen on a regular basis. When something like this happens, physicists shrug and move on, unruffled and unsurprised.

Researchers asked 30 University of Pennsylvania undergraduate to listen to a randomly-assigned piece of music, and then to record their birth dates.

According to their birth dates, people were nearly a year-and-a-half younger
after listening to “When I’m Sixty-Four” (adjusted M = 20.1
years) rather than to “Kalimba” (adjusted M = 21.5 years),
F(1, 17) = 4.92, p = .040.

This is a randomized experiment, not just an observational study, so we can conclude that listening to the Beatles actually changes your date of birth.

The point of the paper was to show that various sorts of sloppy design and modestly dodgy reporting of statistical analyses, especially in small data sets, can lead to finding pretty much anything you want.  You can then issue a press release about it and end up in the newspapers.

Some fields of science already know about this problem and have at least attempted to introduce safeguards. Medical researchers and statisticians have put together reporting guidelines that the better medical journals insist on following. The  CONSORT guidelines for randomized trials are pretty widely accepted.  More recently, STROBE addresses observational studies, and  PRISMA (formerly QUOROM) covers systematic reviews.

There’s a good article in Stuff today on day-care.  The reporters describe the anti-daycare research of Dr Aric Signman being pushed by Family First, but also the reaction of the scientific community to that research.    As usual, no-one links to sources, so as a public service

• Professor Dorothy Bishop’s commentary in the Guardian
• Ben Goldacre’s article in Bad Science
• Dr Sigman’s own disclaimer about the results (“I selected studies that were generally negative precisely because most biologists and policy makers are unaware of the existence of these studies”)

[Update: The Herald now also has a story, and it is also good.  On the other hand, their bogus poll for today asks “Is daycare harmful for young children?”  They could at least stick to questions where majority opinion would be relevant.]

You may remember the story about Auckland air pollution being worse than Tokyo, due to data entry errors by the World Health Organization.  The Science Media Centre has put out a new graphic showing actual air pollution levels around the country and around the world. [They also have the right spelling and location for Dunedin]

Levels are moderately high in the south of the South Island, due largely to the use of wood fires for heating.  It’s worth noting that woodsmoke seems to have different health effects from the car and truck exhaust and factory emissions that dominate the fine-particle air pollution in other places with dirty air.  Seattle, where I used to live, had a similar problem with wood smoke, and there has been a lot of study of the health effects. It looks as though wood smoke has harmful effects on the lungs, especially in triggering asthma attacks, but that it doesn’t have as much effect on the heart. Studies in Seattle find no relationship between heart disease and PM10, in contrast to cities where coal or diesel emissions are the main pollutant and associations are found consistently.

Windblown dust also seems to be less harmful: at the Biometric Society conference in Australia a couple of weeks ago there was a presentation on the 2009 Sydney dust storm, which raised PM10 levels to an amazing 15,000 micrograms per cubic meter.  Even at these massive doses the researchers saw no increase in hospital admissions for cardiovascular disease, and a only modest 15% increase for asthma admissions and 25% increase for asthma hospital visits.

Well, for the past two days, we’ve been listening to our MSc and BSc(Hons) students presenting the results of their research projects.  Here’s a list of titles:

Applying Propensity Scores to Compare Hospital Performance

Order book modelling on the New York Stock Exchange

What Foods are Safe to Eat?

In a Genetic Haystack: Exploring Sparse Microarray Time-Series

Network Meta-Analysis: A Simulation Study and Update

Genome-wide Heterozygosity and Successful Aging in the Cardiovascular Health Study Cohort

Dynamic Advertising Modelling by Implementing Bayesian Forecasting

Occupation-based Socioeconomic Scores: A Path Analysis Approach

Dotcharts in R – What, Whoa and Why

Simulation and Estimation of Stochastic Differential Equations

In or Out? Examining Whether Macroeconomic Variables Help Predict the NZ/US Exchange Rate

Bayesian Estimation of Variance in the Binomial Option Pricing Model

The Introductory Statistics Course: Student Attitudes and Perceived Relevancy

Using Principal Components for the Evaluation Likelihood Ratios for Forensic Trace Evidence

Assessing Genetic Relatedness for Invasive Rats

Hospital Restructuring: was it Harming Us?

Reproducible Research – The Report with Nothing to Hide

Choosing a Transformation or Distance Measure in Ecology: What Do You Throw Away?

Multivariate Extension of ATRIMS Using Copulas with an Application to the Stochastic Volatility Model

A Comparison of Lenth’s Method and APC for the Analysis of Unreplicated Experiments

Constructing Confidence Regions for the Stationary Points of Second Order Response Surfaces

Stepped Wedge Randomised Controlled Trial Design: A Systematic Review and a Case Study

Discrete Choice Modelling with VGAM

Today, the department is running an all-day workshop for high-school teachers.

Everyone has heard of the placebo effect, but a lesser known effect is its counterpart, the so-called nocebo effect, which Wikipedia describes as:

A harmful, unpleasant, or undesirable effects a subject manifests after receiving an inert dummy drug or placebo. Nocebo responses are not chemically generated and are due only to the subject’s pessimistic belief and expectation that the inert drug will produce negative consequences.

In today’s Guardian paper, they’ve printed an edited version of Penny Sarchet’s winning essay on nocebo research in the Wellcome Trust science writing competition. Well worth a read.

Congratulations to one of our department members, Ilze Ziedins, whose research project into improving traffic systems has been funded from the Royal Society of New Zealand’s Marsden Fund.

Her research aims are covered in a story in today’s NZ Herald:

Dr Ziedins said past research has found that when travelling, either by car or through cyberspace, people chose their route without thinking of other people. Statisticians called this behaviour selfish routing, and said it was the cause of long delays and queues.

Road users could already choose to use GPS or webcams to plan their journeys. Backed by the $465,000 grant, Dr Ziedins will investigate whether this more detailed, accurate information could change people’s behaviour and reduce congestion on the road or on the internet.

“The main thing we’re looking at is: ‘Will giving people more information lead to a better distribution of traffic, just in itself? If you more information about the state of the network, will your choices end up making the network work better?,” she said.

The answers to solving these problems were not simply in adding lanes to highways or building more roads.

“In fact, increasing capacity may lead to worse behaviour overall,” said Dr Ziedins.

No, not last week’s snow.  To paraphrase Crocodile Dundee: “That’s not an extreme weather event! This is an extreme weather event.” The graph below shows daily deaths in Chicago, over a fourteen year period.  Do you notice anything?

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In this week’s Stat of the Week the misinterpretation is not primarily the fault of the individual media outlet, since it was present in the original source.  Still, if a press release or a wire service story told you that the Wallabies had a new training regimen that would improve their game without making them fitter, faster, tougher in the scrum, more accurate with kicking, or better at putting in the elbow, you’d ask questions.  We’d like to see science journalism eventually get up to the standard of sports journalism.

The Herald reported “a new study suggests [TV’s] damaging effects may even rank alongside those from smoking and obesity”. If you look at the British Journal of Sports Medicine, that’s what the authors actually say. They go on to say “TV viewing time may have adverse health consequences that rival those of lack of physical activity, obesity and smoking; every single hour of TV viewed may shorten life by as much as 22 min”. The implication that TV has an effect separate from physical activity and obesity, just as it is separate from the effect of smoking, is reinforced when they say that the associations were adjusted for a whole bunch of cardiovascular risk factors: cholesterol, blood pressure, age, gender, weight, blood glucose, etc.   The implied claim is that TV kills in a way that isn’t explained by any of these risk factors: it’s not that TV-watching uses up fewer calories, or that you are more likely to snack while watching.  Perhaps the mechanism is that watching too much TV makes you believe all the health-related advertising and medical news? (more…)

As we all know, mean people suck. But do they earn more?

A US study presented at a management conference today looked at measurements of agreeableness, and found that people (or, at least, men) who rated themselves as less agreeable, cooperative, and flexible earned more money.  This isn’t precisely about `mean’ people, but headline writers around the world spontaneously went for the four-letter word (or just copied each other). (more…)