Dr Karla Diaz-Ordaz


Associate Professor
of Biostatistics


Keppel Street
United Kingdom

020 7927 2065

My primary methodological research area is causal machine learning motivated by high-dimensional electronic health records and genomics data.

My work on treatment effect heterogeneity and optimal treatment regimes is funded through a Wellcome Trust-Royal Society Sir Henry Dale Fellowship (2020-2025).

I am also co-lead in a collaborative research project "Developping statistical machine learning methods for Clinical Trials" based at  the Alan Turing Institute.

Previously, I held a Wellcome Trust-LSHTM Institutional Support Fellowship (2018-2019), an MRC Career Development Award in Biostatistics (2014-2018) and an NIHR Methods Fellowship (2009-2012).

In 2017, I was a visiting scholar to Prof. Mark van der Laan's Computational Biology and Causality group at the School of Public Health, University of California, Berkeley.


I have a PhD in Mathematics from Imperial College London and a MSc in Medical Statistics from the London School of Hygiene and Tropical Medicine.

PhD students:

Oliver Hines (2018- ): MRC London Intercollegiate Doctoral scholarship studying double-robust methods with machine learning in high-dimensional data, with applications to cardio-genetics mediation (joint with Prof Stijn Vansteelandt)

Former PhD students:

Dr Schadrac Agbla (awarded 2019): Instrumental Variable methods for adjusting for nonadherence in cluster randomised trials (joint with Prof Bianca DeStavola). 

Dr Anower Hossain (awarded 2017):  Missing data methodology for cluster randomised trials (joint with Dr Jonathan Bartlett).



Department of Medical Statistics
Faculty of Epidemiology and Population Health


Centre for Statistical Methodology


I am the co-organiser of the School's short course Causal Inference in Epidemiology: Recent Methodological Developments 

I am also the teach on the Advanced Statistical Methods (Causal Inference) sub-module in the MSc in Medical Statistics.

I am also a co-organiser of the Machine Learning Module in the MSc in Health Data Science.


My current work involves doubly-robust estimators paired with the machine learning estimation of the nuisance parameters (e.g. Super Learner estimation). Examples of these are Targeted Minimum Loss estimators (TMLE) and g-estimators with machine learning. These methods are very promising to study causal effects using big data. This is in collaboration with Prof Stijn Vansteelandt (U Ghent).

I am also a co-Principal investigator (together with Prof Chris Holmes) on a project scoping the uses of machine learning in clinical trials, at the Alan Turing Institute.

Previous work involved developing methods for estimating causal treatment effect when there is departures from protocol in a randomised trial (i.e. non-compliance and missing data) using Multiple Imputation (collaboration with Prof James Carpenter). I have also worked in  extending methods for cost-effectiveness analysis, accounting for the bivariate nature of the endpoints (with Prof Richard Grieve).

 Some of my methodological work code can be found in my GitHub page.

I am a member of the Centre for Statistical Methodology, and one of the co-ordinators of the missing data and causal inference themes.

Research Area
Clinical trials
Complex interventions
Economic evaluation
Statistical methods
Bayesian Analysis
Electronic health records
Health economics

Selected Publications

Estimated transmissibility and impact of SARS-CoV-2 lineage B.1.1.7 in England.
Davies NG; Abbott S; Barnard RC; Jarvis CI; Kucharski AJ; Munday JD; Pearson CAB; Russell TW; Tully DC; Washburne AD
Science (New York, N.Y.)
Changes in in-hospital mortality in the first wave of COVID-19: a multicentre prospective observational cohort study using the WHO Clinical Characterisation Protocol UK.
Docherty AB; Mulholland RH; Lone NI; Cheyne CP; De Angelis D; Diaz-Ordaz K; Donegan C; Drake TM; Dunning J; Funk S
The Lancet. Respiratory medicine
Demystifying statistical learning based on efficient influence functions
Hines O; Dukes O; Diaz-Ordaz K; Vansteelandt S
Identifying adults at high-risk for change in weight and BMI in England: a longitudinal, large-scale, population-based cohort study using electronic health records.
Katsoulis M; Lai AG; Diaz-Ordaz K; Gomes M; Pasea L; Banerjee A; Denaxas S; Tsilidis K; Lagiou P; Misirli G
The lancet. Diabetes & endocrinology
Weight Change and the Onset of Cardiovascular Diseases: Emulating Trials Using Electronic Health Records.
Katsoulis M; Stavola BD; Diaz-Ordaz K; Gomes M; Lai A; Lagiou P; Wannamethee G; Tsilidis K; Lumbers RT; Denaxas S
Epidemiology (Cambridge, Mass.)
Invited Commentary: Treatment drop-in: making the case for causal prediction.
Sperrin M; Diaz-Ordaz K; Pajouheshnia R
American journal of epidemiology
The effect of a one-year vigorous physical activity intervention on fitness, cognitive performance and mental health in young adolescents: the Fit to Study cluster randomised controlled trial.
Wassenaar TM; Wheatley CM; Beale N; Nichols T; Salvan P; Meaney A; Atherton K; Diaz-Ordaz K; Dawes H; Johansen-Berg H
The international journal of behavioral nutrition and physical activity
Predicting COVID-19 related death using the OpenSAFELY platform
Williamson EJ; Tazare J; Bhaskaran K; McDonald HI; Walker AJ; Tomlinson L; Wing K; Bacon S; Bates C; Curtis HJ
medRxiv preprint
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