Becoming a probabilist | Simon Harris branches out

20 June 2018
Associate Professor Simon Harris, Department of Statistics
Associate Professor Simon Harris

Meet Associate Professor Simon Harris, a new recruit in the Department of Statistics. Simon, from the United Kingdom, is a probabilist. His research focuses on branching processes, including branching Brownian motions. 

Branching processes can be thought of, roughly, as models for populations of animals that move around in space whilst producing offspring at random during their lifetimes.

If an animal is in a ‘good’ location, its rate of reproduction and family size might be higher, whereas in ‘bad’ locations its death rate might be high or fertility reduced.

Typical questions involving branching processes, Simon explains, might concern the growth rate of a population, how quickly it colonises new territory, or the probability a population survives a certain length of time: “Maybe you could imagine a simple model for the spread of mice across Rangitōtō after a careless tourist allows a couple to stow away in their rucksack and escape”.

Some of his recent collaborative work has also described the genealogical tree for a random sample of individuals chosen in a population at some fixed time.

When Simon was a youngster in the Victorian seaside town of Southport, near Liverpool in north-west England, he wanted to be a zoologist and enjoyed “catching frogs and newts, keeping lizards or breeding tropical fish.”

However, around the age of 16, he realised that he should study maths at university: “I was both good at it and enjoyed it – and it was useful too. It seemed an easy and very natural choice”. 

He did his undergraduate studies at Cambridge, started his PhD there with Welsh mathematician David Williams and then followed Williams to Bath, where he completed his PhD.

Simon got a job at the University of Bath and ended up staying 25 years, thoroughly enjoying the lifestyle of the historic city and being part of an internationally recognised probability group.

Simon says his move to New Zealand was influenced by a number of factors: “Overall, it just felt like time for a change,” he says. “I feel European as well as British, and Brexit and the recent climate in the UK was also a push to look at moving overseas”.  

Another influence was the University of Auckland’s “excellent reputation” for research and teaching and strong Statistics and Mathematics departments.

“I also find the research themes going on here interesting, with many people working on applications to wildlife, conservation, fisheries, the environment or the likes.”

And he was curious, too: “Growing up in UK, New Zealand and Australia have always held great interest and appeal, so when a job came up in Auckland at just the right time, I applied.”

Simon has migrated here with wife Carmen, who is from Andalucía in Spain, and his stepson, Carmen’s son Yeray, 15. Carmen, who had been working for 10 years in a UK school as an administration and resources assistant, has recently started a job with Fuji-Xerox, and Yeray is at Takapuna Grammar School.

“Before moving here, as a typical teenager, he said we would be ruining his life,” recounts Simon, “but in fact he settled happily within just a few days after joining his new school. Sadly, I think what swung it so fast was that he needed a new laptop for school and he could use his mobile phone there too, even using some apps in class – mobiles were completely banned in his UK school.”

The family, based in Devonport, is enjoying Auckland’s quality of life, good food, beach walks, and pleasant climate, says Simon, although now winter has arrived they are still getting used to chilly morning temperatures without central heating in their villa.

In his spare time, Simon indulges his love of planted aquariums and breeding tropical fish, those from the Amazon in particular. He’s happy to report that his specialist aquarium equipment has just cleared New Zealand’s strict biosecurity procedures, so he hopes to set up an aquarium (or two) in the coming months.