Posts written by Atakohu Middleton (125)

Every year, the Department of Statistics offers summer scholarships to a number of students so they can work with our staff on real-world projects. We’ll be profiling them on Stats Chat.

Mengdan (below) is working with Jessica McLay on a project titled The simario R package. She explains:

“The simario R package is a collection of R functions for performing dynamic microsimulation developed by  COMPASS (the Centre of Methods and Policy Application in the Social Sciences at the University of Auckland). Dynamic microsimulation is used to test ‘what if?’ situations.  The starting point of the simulation is a set of attributes for each unit (usually individual) and the attributes (variables) are simulated or updated in annual steps.  User-specified modifications can be made on the variables at the start or any point during simulation in order to see the effects on output attributes of interest.

“A simple demonstration microsimulation model (demo model) using the simario R functions was created two years ago, but the focus since then has been on developing a complicated microsimulation model called Modelling the Early Life Course (MELC).  Compared to the demo model, the MELC model uses newer versions of the simario functions and has had a lot of additional functionality built in.

“What I’m doing for my summer project is ensuring that the newer versions of the simario functions  work properly with the demo model and extend the demo microsimulation model.  The extension includes adding more variables to the system, showcasing the different ways variables can be simulated over time and including more of the functionality that is currently in MELC but not in the demo model.  I will also be checking the documentation for all the functions in the simario package to make it ready to publish as an official R package.

“This is useful research as dynamic microsimulation is increasingly used, especially in government, to help in making policy decisions.  There are a number of programming languages used to create microsimulation models, including those based on C++, C#, SAS, and Java.  However, given the prominence of the R language, a package for microsimulation in R could prove useful and helpful to analysts attempting microsimulation.  The demo model in conjunction with an article (to be written later by COMPASS) will show how to put the functions together to create a working microsimulation model.

“This is my third year of a Bachelor of Science majoring in Statistics and Computer Science.  Initially, I chose statistics because I’m into calculating probabilities, and have been since I was a child. As I learned more about stats, especially analysing data by using software, I appreciated even more how useful the subject is in many areas. Studying statistics has improved my logic thinking and my ability to solve real-life problems with stats techniques.

“For the rest of the summer, I’d like to do something relaxing: hang out with my friends, sleep at home and watch dramas so I can be positive and energetic for next semester.”

Every year, the Department of Statistics offers summer scholarships to a number of students so they can work with our staff on real-world projects. We’ll be profiling them on Stats Chat. 

Manasi is working with Dr Yannan Jiang on a project titled Bariatric surgery and diabetic retinopathy progression. She explains:

“Bariatric surgery is an effective method to achieve rapid weight reduction along with a sustained remission of type 2 diabetes (T2D). However, the effect of the surgery on the progression of diabetes retinopathy (DR) – retinal damage that can lead to loss of vision in both the short and long term – is not documented.

“It is hypothesised that bariatric surgery could be associated with a worsening of DR. In this project, I will be working together with Debbie Chen, a medical student from the Faculty of Medical and Health Sciences, under the joint supervision of Dr Rinki Murphy and Dr Yannan Jiang, to assess the impact of bariatric surgery on DR among patients with T2D.

“This research is very useful, as the results will be used to create the first retinal screening protocols for those having undergone bariatric surgery. So we’ll be creating guidelines to channel limited resources and identify those most at risk.

“I have completed a Bachelor of Science majoring in Psychology and Pharmacology and a Graduate Diploma in Statistics. In 2014 I will be doing my Honours in Statistics.

“Statistics excites me as it is an incredibly diverse field that is applicable to almost everything we do. It is fun to be able to break down large datasets to find patterns and solve problems to get a better understanding of the world around us. The Department of Statistics at the University of Auckland has made the experience especially enjoyable as the lecturers are friendly and approachable and the administration staff are very helpful, creating a great environment in which to learn.

“Over the summer, I will be relaxing by drawing, catching up with family and friends – and I am spending two weeks in India around New Year.”

Every year, the Department of Statistics at the University of Auckland offers summer scholarships to a number of students so they can work with our staff on real-world projects. We’ll be profiling the 2013-2014 summer scholars on Stats Chat. Cennaning is working with Associate Professor  David Scott on a project titled Enhancement of the metaplot package.

Cennaning (right) explains:

“In R, there are three major meta-analysis packages (meta, rmeta and metafor) for producing forest plots. However, the generated plots are quite complicated, and it’s not easy to customise the plots if users lack good R knowledge and experience. The metaPlot package created by former University of Auckland student Edna Lu is used to create flexible forest plots and implements the grid-naming scheme to allow for specific customisations. Basically, it extracts the output generated by these three packages and recreates more flexible plots. This is convenient for users customising complicated plots generated by meta, rmeta and metaphor.

“Currently, only some of the possible outputs from meta can be used by metaPlot to produce forest plots; therefore, in this project, I will try to finish the original aim of the package to enable metaPlot to produce all possible outputs from meta, and then extend this functionality to the other two packages.

“The various features of a standard forest plot will lead to many complications in customising such a plot. If we check out the three major meta-analysis packages, we often find there is often more flexibility needed in the plots than a single function can accommodate. In order to customise the forest plots, users have to scan through all the arguments to make any modifications. If they have a preferred set of formats, they have to specify these arguments every time a similar forest plot is drawn. Therefore, by pursuing this research, we can complete the package that provides these customisations but add further flexibility with a different approach to the function design.

“I have a conjoint Bachelor of Commerce/Bachelor of Science degree, and I am doing a Bachelor of Science (Honours) in Statistics. Studying statistics has greatly improved my problem-solving abilities.

“Statistics is a very useful tool; it’s useful in almost any industry, especially in this age where almost everything we do produces data. Did you know that Netflix’s decision to make the political drama House of Cards, starring Kevin Spacey, was based on mining billions of bits of information collected from its millions of consumers? You can find out more in this article. This is why statistics appeals to me.

“Outside university, I like playing music – I enjoy jamming with different musicians, and I am vice-president of the Guitar Union. Over the summer, I’ll probably be spending some time seeing friends, watching movies and playing computer games.”

Every year, the Department of Statistics at the University of Auckland offers summer scholarships to a number of students so they can work with our staff on real-world projects. We’ll be profiling the 2013-2014 summer scholars on Stats Chat. Tania is working with Dr Stephanie Budgett on a project titled First-time mums: Can we make a difference?

Tania (right) explains:

“This project is based on the ongoing levator ani study (LA, commonly known as the pelvic floor muscles) from the Pelvic Floor Research Group at the Auckland Bioengineering Institute (ABI), which looks at how the pelvic floor muscles change after first-time mums give birth.

“The aim is to see whether age, ethnicity, delivery conditions and other related factors are associated with the tearing of the muscle. Interestingly, the stiffness of the muscle at rest has been identified as a key factor and is being measured by a specially designed device, an elastometer, that was built by engineers at the ABI.

“Pelvic-floor muscle injury following a vaginal delivery can increase the risks for prolapse where pelvic organs, such as the uterus, small bowl, bladder and rectum, descend and herniate. Furthermore, the muscle trauma may also promote or intensify urinary and/or bowel incontinence.

“Not only do these pelvic- floor disorders cause discomfort and distress, and reduce the mother’s quality of life, and, if left untreated, may lead to major health concerns later in life. Therefore, a statistical model based on key factors elucidated from the study may aid health professionals in deciding the best strategy for delivering a woman’s baby and whether certain interventions are needed.

“I have recently completed my third year of a Bachelor of Science majoring in Statistics and Pharmacology and intend to pursue postgraduate studies. I hope to integrate my knowledge of medical sciences and statistics and specialise in medical statistics.

“Statistics appeals to me because it is a useful field with direct practical applications in almost every industry. I had initially taken the stage one paper as a standalone in order to broaden my knowledge, but eventually realised that I really liked the subject and that it could complement whichever career I have. That’s when I decided to major in statistics, and I’m very glad that I did.

“Over this summer, aside from the project, I am hoping to spend more time with friends and family – especially with my new baby brother! I am also looking forward to visiting the South Island during the Christmas break.”

Every year, the Department of Statistics at the University of Auckland offers summer scholarships to a number of students so they can work with our staff on real-world projects. We’ll be profiling the 2013-2014 summer scholars on Stats Chat. Ryan is working with Dr Yannan Jiang on research titled Evaluation and comparison of the nutrient profile of processed foods in Australia and New Zealand.   

 Ryan (right) explains:

 “Our project centres around the nutritional content of processed food products available for purchase throughout New Zealand and Australia, based on a Nutrient Profiling Scoring Criterion (NPSC) developed by Food Standards Australia New Zealand, and employed by the FoodSwitch smartphone application to identify healthier food choices.

“Using FoodSwitch databases of Australian and New Zealand packaged processed foods, our aim is to determine whether each individual product reaches a particular threshold value that would allow the producer to make a health claim regarding the product.

“We are specifically interested in determining the proportion of foods across Australia and New Zealand that meet their respective threshold values, the mean NPSC score for individual food categories, and the association between NPSC score and each individual nutrient component (eg energy, saturated fat, sodium and sugar).

“With the continuing upward trend in both unhealthy diets and worldwide obesity, identifying and consuming healthy food products is becoming increasingly important. The integration of the NPSC data with the FoodSwitch smartphone application, available in both Australia and New Zealand, allows everyday consumers to compare products and identify healthier alternatives using a streamlined, three-tiered system.

“Salient differences exist between the two countries. Previous work conducted by the National Institute for Health Innovation (NIHI), for example, showed that the salt content of bread was notably different in the two countries despite dietary similarities – and despite the fact that many producers operate in both Australia and New Zealand.

“I’ve just finished my penultimate year of a Bachelor of Commerce and Bachelor of Science, majoring in Finance, Marketing, Statistics, and Psychology, and I plan to study Honours in Finance in 2015. Outside of university, I have a keen interest in sport, particularly NFL and golf, and am partial to a wager or two at the casino.

“I initially picked up statistics as a major in my second year of study, having decided to drop physiology. I’d been told that statistics was applicable in almost all aspects of life, and was sucked in by Wayne Stewart’s uniquely captivating lecturing style in Stats 208; it’s a crying shame he’s no longer teaching it! (Note from the ed: Wayne was well-known for a teaching approach that used puppets, songs and audience participation; he’s now teaching at the University of Oklahoma in the US). I’ve found that statistics complements my three other majors, and was what initially sparked my interest in researching the odds of gambling.”

Every year, the Department of Statistics at the University of Auckland offers summer scholarships to a number of students so they can work with our staff on real-world projects. We’ll be profiling the 2013-2014 summer scholars on Stats Chat. Callum is working with Dr Ian Tuck on a project titled Probability of encountering a bus.  

Callum (right) explains:

“If you encounter a bus on a journey, you are likely to be exposed to higher levels of pollution. I am trying to find the probability of encountering a bus and how many you will encounter when you travel from place A to place B, taking into account variables such as the time of day and mode of transport.

“This research is useful because it will give us more of an understanding about the impact that buses have on our daily exposure to pollution. we can use this information to plan journeys and learn more about an issue that is becoming more and more apparent.

“I was born in Auckland and have lived here my whole life. I just finished my third year of a Bachelor of Commerce/Bachelor of Science conjoint majoring in Accounting, Finance, and Statistics, which I will finish at
the end of 2014.

“Statistics appeals to me because it is used everyday in conjunction with many other areas. It is very useful to know in a lot of workplaces, and it is interesting because it has a lot of real-life applications.

“I am going to Napier for Christmas and Rhythm and Vines for New Year. In the rest of my spare time, I will be playing cricket and golf, as well as hanging out with friends.”

Every year, the Department of Statistics at the University of Auckland offers summer scholarships to a number of students so they can work with our staff on real-world projects. We’ll be profiling the 2013-2014 summer scholars on Stats Chat.

Ashley (right) is working with Dr Paul Murrell on a project entitled  Grid-based graphs in R.

Ashley explains:

“There’s a wonderful piece of software called graphviz that does a great job of making node and edge graphs that look really good. My research is about expanding an R package called gridGraphviz, which has graphviz lay out a graph, then uses the R ‘grid’ graphics package to draw the graph.

“This research is useful as current node and edge packages in R draw graphs using R’s default ‘graphics’ package. Building a package that uses the ‘grid’ package means we can take advantage of all the flexibility that ‘grid’ allows, including making interactive graphs and exporting our plots in a variety of useful formats. We also hope it will make very good-looking graphs.”

More about Ashley:

“I have a BA in philosophy, and have just finished my second year of a BSc in Statistics. I would like to train to be a high school teacher after I graduate.

“When I finished my compulsory high-school maths classes, I swore I would never use maths again, and set about becoming a philosopher. Much to my surprise, I found that philosophy and logic led me to become very, very interested in mathematics, enough that I decided I wanted to return to university and learn all about it.

“Statistics is, for me, a meeting place of my interest in mathematics and computer programming. It can allow us to produce something that can communicate useful ideas about the world to other people. It’s a form of literacy I honestly had no idea I was missing out on until I came back to learn about it.

“This summer, I’m going to spend a few weeks travelling around the South Island treating myself to some wonderful summer weather.”

The New Zealand media is self-regulating – that is, it governs its own, and the Press Council is the port of call for public complaints about print media. Two complaints that have been upheld recently focused on the use/abuse of statistical information. I’m posting about these  not to take a dig at my esteemed colleagues, but to point out how we can avoid falling into a hole and/or creating a damaging, discriminatory or dangerous urban myth.

The first complaint concerns the The Press (Weekend) newspaper, which published an article on Saturday October 12, 2013, about health data from the Canterbury District Health Board concerning the increase in the sexually-transmitted infection chlamydia in the region since 2011. The headline of the article was Luck of the Irish has downside in sex-disease stats. The intro read “Irish workers helping with the rebuild are sharing the love but it seems they may also be helping to spread sexual disease.”

The Press Council noted there was no statistical information given to support the statements linking the Irish to the chlamydia. The link between the Irish nationals and the chlamydia statistics was of the newspaper’s making and not supported by any reported information, making the report inaccurate and discriminatory.  Read the full decision here.

The second complaint concerns the Dominion Post. On August 12, 2013, under the headline Boys slip further in school’s co-ed class, the paper published a story and table about achievement rates in 2012 for NCEA level 3 students in its circulation area, with the table reporting on highest and lowest achieving schools. The table gave pass rates for the highest achieving schools, but failure rates for the lowest achieving schools. Under the heading “Lowest Achieving Hawke’s Bay Schools” the table listed Wairoa High School 43.8% not achieved; Dannevirke High School: 40%; Taradale High School: 36.2%. The school complained that this conveyed a misleading impression that only 36.2% of its students had passed. In fact, 63.8% had.

It turns out that the original NZQA figures showed the number of year 13 students who had NOT passed NCEA level 3. The newspaper said that it had decided to turn the figures around to assist readers and also show how well most schools and students had performed.  In upholding the complaint, the Press Council said “A table provides readers with a quick and ready means of assessing data. But when a comparison is being made it is important that the data is presented in such a way as to make the comparison valid. The use of two differing measures of data in the same table was therefore confusing and misleading.” The editor said, ” … I do accept that we would have been better advised to have used only one measure throughout. I am happy to give an undertaking that we will not be using that format again.” Read the full decision here.

… according to the 2013 Census figures,

• 51 would be female, 49 male.
• 70 would be European, 14 Maori and 11 Asian.
• 24 would have been born overseas
• 21 would have a tertiary qualification
• 4 would be unemployed.
• 4 would earn over $100,000

Statistics New Zealand has done a nice graphic of the above, too. Full 2013 Census info available here.

Local media have been proclaiming that younger women are binge-drinking themselves into oblivion, (examples here and here),  many of these stories leaning on Canadian journalist and recovering alcoholic Ann Dowsett Johnston’s book Drink: The Intimate Relationship Between Women and Alcohol.  She says the percentage of college students who binge drink, using the measure of consuming five or more drinks in one sitting, was nearly 45% in 2011, and repeated this in a recent Wall Street Journal item called The New Face of Risky Drinking is Female.

However, there is an editor’s note at the bottom of her piece (that probably should be at the top), pointing out that Johnston got her compelling  figure by combining the results  of two separate studies carried out in different years.

The  non-profit, non-partisan Statistical Assessment Service (STATS) in the US points out that a basic tenet of Statistics 101 is that one should never directly compare survey results that come from different populations or that were provided from surveys taken with different methods, even if the surveys are angling for the same kind of data.  Surveys can return different results for a variety of reasons, from the time of year in which they are administered, to the population from which participants are chosen, and even to how the questions are asked. In this case, it says, both surveys  have systematic biases that come from their survey methods, which in turn makes direct comparisons problematic. See its useful analysis of the situation here.