News, PhD projects

Migration and Movement SRT project

Dr Eleni Matechou and Dr Bruno Santos have been awarded funding from the Migration and Movement SRT for their project on Modelling Human Population Registers.

PROJECT TITLE: MODELLING OF HUMAN POPULATION REGISTERS

Supervisors: The PhD student will be supervised by an interdisciplinary team across four international institutions, with expertise in

(1)  Statistics (Dr Bruno Santos) and Statistical Ecology (Dr Eleni Matechou), University of Kent, Canterbury, England

(2) Demography (Dr Eleonora Mussino), University of Stockholm, Sweden

(3)  Bayesian Inference/Statistical Ecology (Professor Ruth King), University of Edinburgh, Scotland

(4) Ecology/Statistical Ecology (Dr Blanca Sarzo), University of Valencia, Spain

Research background: Monitoring the size and characteristics of human populations using official censuses is a lengthy and costly process. As a result, in recent years, there has been an increased focus on using a statistical framework instead, referred to as multiple systems estimation (MSE), to infer population size of specific groups using opportunistic registers and incomplete lists. Examples include estimating the number of drug users in a city [1] and the number of victims of human trafficking [2]. MSE builds on well-established statistical theory and models, and can be employed using existing software [3]. However, MSE does not follow the same individuals over time to learn from their past experiences or behaviours and hence cannot account for individual heterogeneity in the probability of being observed in one or more registers, for dependence between individuals or to identify the factors behind temporary emigration.

These incomplete and imperfect human population registers are similar to ecological data, referred to as capture-recapture (CR) data, collected on wildlife populations, such as birds and mammals [4]. The corresponding ecological CR models have the same aims as MSE, namely estimating population size and monitoring population characteristics, but rely on completely different modelling approaches, with a strong focus on modelling individual time series [5]. However, CR models are computationally more demanding than MSE, and as a result do not scale well to large populations [6].

Project aims: The project aims to bring together MSE and CR modelling approaches and provide a general and unifying modelling framework for human population registers. The new models to be developed will overcome the shortcomings of the existing approaches, and hence will be applicable to high-dimensional data sets typically observed in human populations, and increasingly in wildlife populations, whilst at the same time modelling individual time-series data.

The models will be applied to data from several countries that routinely collect register data, such Sweden, Norway and Italy. We will obtain estimates of population size for different sub-populations, such as the migrant population each year, as well as of the probability of individuals of certain characteristics, such as age, sex etc., to appear in each register, e.g. employment. These estimates will then be compared to currently used metrics by each country to quantify the effect of over-coverage, which is the bias introduced by considering individuals who are not part of the population in demographic rates, such as mortality. The developed models and corresponding code will be made freely available and the methods will be disseminated through close collaboration with demographers in the different countries and corresponding workshops, as appropriate.

References

[1] King, R., Bird, S. M., Overstall, A. M., Hay, G., & Hutchinson, S. J. (2014). Estimating prevalence of injecting drug users and associated heroin‐related death rates in England by using regional data and incorporating prior information. Journal of the Royal Statistical Society: Series A (Statistics in Society), 177(1), 209-236. [2] Zhang, S. X., & Larsen, J. J. (2021). Estimating the size of the human trafficking problem: MSE and other strategies. Crime & Delinquency, 67(13-14), 2169-2187. [3] Overstall, A., & King, R. (2014). conting: An R package for Bayesian analysis of complete and incomplete contingency tables. Journal of Statistical Software, 58(7), 1-27. [4] McCrea, R. S., & Morgan, B. J. (2014). Analysis of capture-recapture data. CRC Press. [5] Matechou, E., & Argiento, R. (2022). Capture-recapture models with heterogeneous temporary emigration. Journal of the American Statistical Association, (just-accepted), 1-32. [6] King, R., Sarzo, B., & Elvira, V. (2022). Large Data and (Not Even Very) Complex Ecological Models: When Worlds Collide. arXiv preprint arXiv:2205.07261.

Research excellence: The student will join the thriving Statistical Ecology @ Kent research group, and the Migration and Movement Signature Research Theme, being supervised by leading researchers in demography, statistics and statistical ecology. They will also be members of the UK-wide National Centre for Statistical Ecology. They will attend London Taught Course Centre training, NCSE seminars, and SE@K specialist training and they will present research results at a range of appropriate national and international conferences. There will be ample opportunity for independent development, with the student gaining transferable knowledge of modern data science and statistics.

Please email Dr Eleni Matechou (e.matechou@kent.ac.uk) if you are interested in applying for the project or have any questions about the project or the application process.

Application Process

Applicants should follow the University of Kent’s online application process.

Please create an account and add your personal details as requested. Subsequently, you need to select your starting date (September 2023) and write your personal statement (see below). Choose “Other” for source of funding and “Definite” for funding. Add details of your qualifications, and then in the Research Information Tab, write “Dr Eleni Matechou” under supervisor and the title of the project (“Modelling of human population registers“) as the research topic. You do not need to add a research proposal.

As part of the process, you need to provide the following:

o   details of your qualifications;

o   two academic references;

o  a personal statement

The statement must be maximum 500 words detailing (1) your reason for applying for a doctoral studentship (i.e, why do you want to pursue doctoral studies) and (2) your fit with the proposed project (how your educational/professional/personal background has prepared you well to undertake research in this topic).

Entry Requirements

We seek a candidate with a strong quantitative background, for example an MSc in Statistics or an MSc with high statistics content, or a background in demographic modelling. Experience coding in R, or similar, is essential.

The University of Kent requires all non-native speakers of English to reach a minimum standard of proficiency in written and spoken English before beginning a postgraduate degree. For more information on English language requirements, please visit this page.

About the Migration and Movement Signature Research Theme (SRT)

The Migration and Movement SRT is a vibrant community of over 100 scholars and practitioner academics working in the field of migration and movement, led by Prof. David Herd (English), Dr Bahriye Kemal (English), Dr Amanda Klekowski von Koppenfels (Politics), Dr Margherita Laera (Drama), Dr Tom Parkinson (Higher Education) and Dr Sweta Rajan-Rankin (Sociology). Members bring a number of interdisciplinary perspectives, from International Law to Urban Planning, Medicine, Health, Pharmacy, Statistics, Politics and Entrepreneurship. The SRT aims to expand our understanding of migration beyond the movement of people to include the migration of pathogens, remittances, technologies, cultures, scriptures, coffee, drugs, medicines, labour, and ideas.

The Migration and Movement SRT was launched in September 2021, at a historical moment when intersecting crises of movement were (and still are) taking place. As the COVID-19 pandemic was spreading, governments were enforcing lockdowns and movement restrictions, yet the UNHCR reported forced displacement at upwards of 75 million people. The year 2022 opened with new refugee crises in Ukraine and Ethiopia, while climate catastrophes and other military conflicts reaped havoc across the planet, notably in Pakistan. People facing hardship will continue to seek sustainable existences elsewhere and will be compelled to move, yet governments in the global north are preparing to render the seeking of asylum more difficult or even illegal.

As a public-facing, civic-oriented research group, we believe universities – the University of Kent  in particular – can play a key role as leaders of intellectual debates and as creators of advocacy and evidence-based research around migration, its contexts, histories and benefits. We are committed to learning from the work of decolonial and postcolonial colleagues, and from the perspectives of persons with lived experience. Reflexive learning and intersectional empathy underpin every aspect of our ethics. We are keen to foster the next generation of scholars working on issues of migration and movement, broadly conceived, and welcome applications from scholars currently living in all parts of the world. For more information on the Migration and Movement SRT, please visit: https://research.kent.ac.uk/signature-themes/migration-and-movement/

 Scholarship Information

Signature Research Theme scholars will receive the following:

  • Annual stipend at UKRI rates (£17,668 in 2022/23);
  • Annual tuition fees at Home rates (£4,596 in 2022/23)

o   2023/24 rates to be announced.

Home and International candidates are eligible to apply. The Abdulrazak Gurnah Doctoral Scholarship will cover International fees, while the Migration and Movement Doctoral Scholarship will cover Home fees only, including for those with UK settled or pre-settled status.

 

Selection Process

Supervisors will carry out the initial eligibility checks and shortlisting. All shortlisted candidates will then be ratified at Division level where a further selection process might occur. Four final shortlisted candidates per project will be submitted to the SRT Studentship Selection Panel.

Shortlisted candidates will be invited for an interview taking place the week commencing 27 February 2023.

Deadline

The deadline for  applications is midnight on 3 February.

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News, Papers

JASA paper by Eleni and Raffaele

The paper, titled “Capture-recapture models with heterogeneous temporary emigration”, first published online on the 14th of September 2022, develops a novel modelling framework for capture-recapture data without relying on the assumption of permanent emigration. The model is built within a Bayesian non-parametric & changepoint process framework, and is demonstrated on data on salmon anglers in Norway.

 

 

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Uncategorized

rGAI: An R package for fitting the generalized abundance index to seasonal count data

Emily Dennis, Calliste Fagard-Jenkin and Byron Morgan have created an R package for fitting the generalized abundance index to seasonal count data. The work has been published in Ecology and Evolution in the paper “rGAI: An R package for fitting the generalized abundance index to seasonal count data”.

The paper can be found at: https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.9200

The R package is available at: https://github.com/calliste-fagard-jenkin/rGAI

 

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Uncategorized

Statistical Ecology Conference

Members of SE@K group attended ISEC from 27th June to 1st July. Some went to South Africa to attend in person others attended virtually.

Eleni, Alex and Ioannis gave a half day workshop on Modelling environmental DNA data.

Eleni presented work on Capture recapture models with heterogeneous temporary.

Alex gave a talk on A unifying modelling framework for metabarcoding data.

Rachel talked on Model selection for integrated population models: selecting age structure with multiple data types.

James’ presentation was on Accounting for varying spatial scales in the production of UK butterfly abundance estimates.

Diana talked about Bayesian Identifiability in Ecological Models.

Fay presented work on Assessing the success of reintroductions whilst accounting for multispecies populations.

Bryon talked about Fitting dynamic occupancy models to very large occurrence data sets using hidden Markov models.

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grants, News

Eleni awarded Knowledge Transfer Partership with NatureMetrics

NatureMetrics is an innovative, science-based, women-led SME that commercialises environmental DNA-based biodiversity monitoring solutions at scale.  They are world leaders in delivering powerful, scalable biodiversity data collected safely and sustainably using environmental DNA.  NatureMetrics work to develop end-to-end and automated tools for biodiversity detection in the field, to be used by non-experts.

 

This KTP aims to develop and integrate new statistical techniques for addressing two challenges associated with biodiversity surveys using environmental DNA: accounting for error and noise in environmental DNA surverys, and optimising survey design. These techniques will improve the business’s decision-support tools for nature conservation and restoration, facilitating access to new markets.

 

NatureMetrics’ mission is to bridge the gap between molecular techniques and environmental management by using cutting-edge DNA analysis to monitor biodiversity and measure natural capital in the environment and this KTP will enable them to achieve this mission.

 

Specifically, the aim of this KTP is to embed new knowledge and capabilities of Bayesian hierarchical statistical models developed by academics at the University of Kent (Dr Eleni Matechou) and University College London (Professor Jim Griffin). Through this KTP, these techniques will be integrated into NatureMetrics’ analysis workflows, enabling them to increase confidence levels around the presence/absence or relative abundance of surveyed biological communities (i.e. collections of species at a site) in downstream products.  This will optimise the cost and effort needed to collect and analyse samples.

 

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Conferences/Meetings/Workshops, News

The role of statistics in decision-making at the landscape scale

The recordings of the invited session, organised by Eleni as Chair of the Environmental Statistics Section, at the 2021 RSS conference are available on the RSS youtube channel 

Landscapes are continuously changing, either naturally of because of human intervention. It is important to understand these changes, their short- and long-term effects and the associated risks, and to make decisions on the need and way to stop or reverse changes when required. This session demonstrated how statistics are currently used to inform decision-making at the landscape scale, with pollinators, animal populations, air pollution and droughts as case studies and will highlight emerging statistical challenges within landscape decision-making, specifically around assimilating data from both numeric and non-numeric perspectives.

The session, which took place on Wednesday 8 September 2021 14.20-15.40, featured talks by Mark Brewer (BiOSS), Richard Everitt (Warwick), Emma Gardner (Reading) and Carly Stevens c.stevens@lancaster.ac.uk (Lancaster)

 

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