arXiv subjects

Catherine Hurley

Publications and source records attributed to Catherine Hurley.

8 recordsLinked to original sources

arXiv2026

Using Time Series Measures to Explore Family Planning Survey Data and Model-based Estimates

Family planning is a global development priority and a key indicator of reproductive health. Monitoring progress is challenged by gaps in survey data across countries. The United Nations Population Division addresses this with the Family Planning Estimation Model (FPEM), a Bayesian hierarchical time series model producing annual estimates of modern contraceptive use while sharing information across countries and regions. This paper evaluates how well FPEM estimates align with survey data using time series diagnostic indices from the wdiexplorer R package, which account for countries nested within sub-regions. Visualisation of survey data, modelled trajectories, and diagnostics enables assessment of model performance, highlighting where trends align and where discrepancies occur.

stat.AP↗

arXiv2025

wdiexplorer: An R package Designed for Exploratory Analysis of World Development Indicators (WDI) Data

The World Development Indicators (WDI) database provides a wide range of global development data, maintained and published by the World Bank. Our \textit{wdiexplorer} package offers a comprehensive workflow that sources WDI data via the \textit{WDI} R package, prepares and explores country-level panel data of the WDI through computational functions to calculate diagnostic metrics and visualise the outputs. By leveraging the functionalities of \textit{wdiexplorer} package, users can efficiently explore any indicator dataset of the WDI, compute diagnostic indices, and visualise the metrics by incorporating the pre-defined grouping structures to identify patterns, outliers, and other interesting features of temporal behaviours. This paper presents the \textit{wdiexplorer} package, demonstrates its functionalities using the WDI: PM$_{2.5}$ air pollution dataset, and discusses the observed patterns and outliers across countries and within groups of country-level panel data.

stat.CO↗

arXiv2025

PieGlyph: An R package for creating axis invariant pie-glyphs for 2d plots

Effective visualisation of multidimensional data is crucial for generating insights. Glyph-based visualisations, which encode data dimensions onto multiple visual channels such as colour, shape, and size, provide an effective means of representing complex datasets. Pie-chart glyphs (pie-glyphs) are one such approach, where multiple data attributes are mapped to slices within a pie chart. This paper introduces the PieGlyph R package, which enables users to overlay any 2D plot with axis-invariant pie-glyphs, offering a compact and intuitive representation of multidimensional data. Unlike existing R packages such as scatterpie or ggforce, PieGlyph generates pie-glyphs independently of the plot axes by employing a nested coordinate system, ensuring they remain circular regardless of changes to the underlying coordinate system. This enhances interpretability, particularly in when visualising spatial data, as users can select the most appropriate map projection without distorting the glyphs' shape. Pie-glyphs are also particularly well-suited for visualising compositional data, where there is a natural sum-to-one constraint on the data attributes. PieGlyph is developed under the Grammar of Graphics paradigm using the ggplot2 framework and supports the generation of interactive pie-glyphs through the ggiraph package. Designed to integrate seamlessly with all features and extensions offered by ggplot2 and ggiraph, PieGlyph provides users with full flexibility in customising every aspect of the visualisation. This paper outlines the conceptual framework of PieGlyph, compares it with existing alternatives, and demonstrates its applications through example visualisations.

cs.HC↗

arXiv2024

Visualisation for Exploratory Modelling Analysis of Bayesian Hierarchical Models

When developing Bayesian hierarchical models, selecting the most appropriate hierarchical structure can be a challenging task, and visualisation remains an underutilised tool in this context. In this paper, we consider visualisations for the display of hierarchical models in data space and compare a collection of multiple models via their parameters and hyper-parameter estimates. Specifically, with the aim of aiding model choice, we propose new visualisations to explore how the choice of Bayesian hierarchical modelling structure impacts parameter distributions. The visualisations are designed using a robust set of principles to provide richer comparisons that extend beyond the conventional plots and numerical summaries typically used. As a case study, we investigate five Bayesian hierarchical models fit using the brms R package, a high-level interface to Stan for Bayesian modelling, to model country mathematics trends from the PISA (Programme for International Student Assessment) database. Our case study demonstrates that by adhering to these principles, researchers can create visualisations that not only help them make more informed choices between Bayesian hierarchical model structures but also enable them to effectively communicate the rationale for those choices.

stat.ME↗

arXiv2023

Going beyond richness: Modelling the BEF relationship using species identity, evenness, richness and species interactions via the DImodels R package

BEF studies aim to understand how ecosystems respond to a gradient of species diversity. Diversity-Interactions (DI) models are suitable for analysing the BEF relationship. These models relate an ecosystem function response of a community to the identity of the species in the community, their evenness (proportions) and interactions. The number of species in the community (richness) is also implicitly modelled through this approach. It is common in BEF studies to model an ecosystem function as a function of richness; while this can uncover trends in the BEF relationship, by definition, species diversity is much broader than richness alone, and important patterns in the BEF relationship may remain hidden. In this paper, we introduce the DImodels R package for implementing DI models. We also compare DI models to traditional modelling approaches to highlight the advantages of using a multi-dimensional definition of species diversity. We show that using DI models can lead to considerably improved model fit over other methods; it does this by incorporating variation due to the multiple facets of species diversity. Predicting from a DI model is not limited to the study design points, the model can extrapolate to predict for any species composition and proportions (assuming there is sufficient coverage of this space in the study design). Expressing the BEF relationship as a function of richness alone can be useful to capture overall trends. However, collapsing the multiple dimensions of species diversity to a single dimension (such as richness) can result in valuable ecological information being lost. DI modelling provides a framework to test the multiple components of species diversity in the BEF relationship. It facilitates uncovering a deeper ecological understanding of the BEF relationship and can lead to enhanced inference.

q-bio.PE↗

arXiv2022

vivid: An R package for Variable Importance and Variable Interactions Displays for Machine Learning Models

We present vivid, an R package for visualizing variable importance and variable interactions in machine learning models. The package provides a range of displays including heatmap and graph-based displays for viewing variable importance and interaction jointly and partial dependence plots in both a matrix layout and an alternative layout emphasizing important variable subsets. With the intention of increasing a machine learning models' interpretability and making the work applicable to a wider readership, we discuss the design choices behind our implementation by focusing on the package structure and providing an in-depth look at the package functions and key features. We also provide a practical illustration of the software in use on a data set.

stat.CO↗

arXiv2022

Visualizations for Bayesian Additive Regression Trees

Tree-based regression and classification has become a standard tool in modern data science. Bayesian Additive Regression Trees (BART) has in particular gained wide popularity due its flexibility in dealing with interactions and non-linear effects. BART is a Bayesian tree-based machine learning method that can be applied to both regression and classification problems and yields competitive or superior results when compared to other predictive models. As a Bayesian model, BART allows the practitioner to explore the uncertainty around predictions through the posterior distribution. In this paper, we present new visualization techniques for exploring BART models. We construct conventional plots to analyze a model's performance and stability as well as create new tree-based plots to analyze variable importance, interaction, and tree structure. We employ Value Suppressing Uncertainty Palettes (VSUP) to construct heatmaps that display variable importance and interactions jointly using color scale to represent posterior uncertainty. Our new visualizations are designed to work with the most popular BART R packages available, namely BART, dbarts, and bartMachine. Our approach is implemented in the R package bartMan (BART Model ANalysis).

stat.CO↗

arXiv2021

Visualizing Variable Importance and Variable Interaction Effects in Machine Learning Models

Variable importance, interaction measures, and partial dependence plots are important summaries in the interpretation of statistical and machine learning models. In this paper we describe new visualization techniques for exploring these model summaries. We construct heatmap and graph-based displays showing variable importance and interaction jointly, which are carefully designed to highlight important aspects of the fit. We describe a new matrix-type layout showing all single and bivariate partial dependence plots, and an alternative layout based on graph Eulerians focusing on key subsets. Our new visualizations are model-agnostic and are applicable to regression and classification supervised learning settings. They enhance interpretation even in situations where the number of variables is large. Our R package vivid (variable importance and variable interaction displays) provides an implementation.

stat.CO↗