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Christopher C Holmes

13 accepted papers

2025

Hierarchical Bias-Driven Stratification for Interpretable Causal Effect Estimation

AISTATS 2025poster

Modelling causal effects from observational data for deciding policy actions can benefit from being interpretable and transparent; both due to the high stakes involved and the inherent lack of ground truth labels to evaluate the accuracy of such models. To date, attempts at transparent causal effect…

Cited by 0SourcecodeScholar
2025

Is Merging Worth It? Securely Evaluating the Information Gain for Causal Dataset Acquisition

AISTATS 2025poster

Merging datasets across institutions is a lengthy and costly procedure, especially when it involves private information. Data hosts may therefore want to prospectively gauge which datasets are most beneficial to merge with, without revealing sensitive information. For causal estimation this is part…

Cited by 0SourcecodeScholar
2025

On Subjective Uncertainty Quantification and Calibration in Natural Language Generation

AISTATS 2025poster

Applications of large language models often involve the generation of free-form responses, in which case uncertainty quantification becomes challenging. This is due to the need to identify task-specific uncertainties (e.g., about the semantics) which appears difficult to define in general cases. Thi…

Cited by 0SourcecodeScholar
2024

Is In-Context Learning in Large Language Models Bayesian? A Martingale Perspective

ICML 2024poster

In-context learning (ICL) has emerged as a particularly remarkable characteristic of Large Language Models (LLM): given a pretrained LLM and an observed dataset, LLMs can make predictions for new data points from the same distribution without fine-tuning. Numerous works have postulated ICL as approx…

2023

A Unified Framework for U-Net Design and Analysis

NeurIPS 2023poster

U-Nets are a go-to neural architecture across numerous tasks for continuous signals on a square such as images and Partial Differential Equations (PDE), however their design and architecture is understudied. In this paper, we provide a framework for designing and analysing general U-Net architecture…

2023

Differentially Private Statistical Inference through $\beta$-Divergence One Posterior Sampling

NeurIPS 2023poster

Differential privacy guarantees allow the results of a statistical analysis involving sensitive data to be released without compromising the privacy of any individual taking part. Achieving such guarantees generally requires the injection of noise, either directly into parameter estimates or into th…

Cited by 7SourcePDFScholar
2023

PWSHAP: A Path-Wise Explanation Model for Targeted Variables

ICML 2023poster

Predictive black-box models can exhibit high-accuracy but their opaque nature hinders their uptake in safety-critical deployment environments. Explanation methods (XAI) can provide confidence for decision-making through increased transparency. However, existing XAI methods are not tailored towards m…

2022

A Multi-Resolution Framework for U-Nets with Applications to Hierarchical VAEs

NeurIPS 2022accept

U-Net architectures are ubiquitous in state-of-the-art deep learning, however their regularisation properties and relationship to wavelets are understudied. In this paper, we formulate a multi-resolution framework which identifies U-Nets as finite-dimensional truncations of models on an infinite-dim…

Cited by 10SourcePDFScholar
2021

Improving VAEs' Robustness to Adversarial Attack

ICLR 2021poster

Variational autoencoders (VAEs) have recently been shown to be vulnerable to adversarial attacks, wherein they are fooled into reconstructing a chosen target image. However, how to defend against such attacks remains an open problem. We make significant advances in addressing this issue by introduci…

Cited by 36SourcePDFScholar
2021

Multi-Facet Clustering Variational Autoencoders

NeurIPS 2021poster

Work in deep clustering focuses on finding a single partition of data. However, high-dimensional data, such as images, typically feature multiple interesting characteristics one could cluster over. For example, images of objects against a background could be clustered over the shape of the object an…

2021

Neural Ensemble Search for Uncertainty Estimation and Dataset Shift

NeurIPS 2021poster

Ensembles of neural networks achieve superior performance compared to standalone networks in terms of accuracy, uncertainty calibration and robustness to dataset shift. Deep ensembles, a state-of-the-art method for uncertainty estimation, only ensemble random initializations of a fixed architecture.…

2021

On Locality of Local Explanation Models

NeurIPS 2021poster

Shapley values provide model agnostic feature attributions for model outcome at a particular instance by simulating feature absence under a global population distribution. The use of a global population can lead to potentially misleading results when local model behaviour is of interest. Hence we c…