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Karla Diaz-Ordaz

BSc MSc PhD

Assistant Professor
in Biostatistics

I have a PhD in Pure Mathematics from Imperial College London (Ergodic Theory) and a MSc in Medical Statistics from the London School of Hygiene and Tropical Medicine in September 2011. 

I worked at the Pragmatic Clinical Trial Unit, Centre for Primary Care and Public Health, Queen Mary, as part of a three-year NIHR Methods Fellowship in Medical Statistics.

I have also experience in cost-effectiveness analysis of cluster randomised trial data.

I currently hold an MRC Career Development Award in Biostatistics.

Affiliations

Faculty of Epidemiology and Population Health
Department of Health Services Research and Policy
Department of Medical Statistics

Centres

Statistical Methodology

Teaching

I am the co-organiser of the School's short courses Statistical Analysis with Missing Data using Multiple Imputation and Inverse Probability Weighting and Causal Inference in Epidemiology: Recent Methodological Developments 

I am also co-organiser of the two Bayesian Modules in the MSc in Medical Statistics.

Research

I am primarily interested in causal inference methodology, to deal with confounding and missing data, in both clinical trials and observational studies.

I am currently working in 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. This work is in collaboration with Profs Michael Kenward and James Carpenter.  

Another strand of my current work involves doubly-robust estimators, in particular, those that can be paired with the use of ensemble machine learning methods, e.g. Targeted Minimum Loss estimators (TMLE). These methods are very promising when dealing with big data.

 I have also worked in methods to analyse missing clustered data.  Currently, I study and compare the performance of different multiple imputation techniques to handle whole clusters non-response (empty clusters).    I am also interested in extending such methods for cost-effectiveness analysis, accounting for the bivariate nature of the endpoints.

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

Research Area
Clinical trials
Complex interventions
Economic evaluation
Statistical methods
Bayesian Analysis
Electronic health records
Methodology
Discipline
Economics
Epidemiology
Statistics

Selected Publications

Multiple imputation methods for bivariate outcomes in cluster randomised trials.
DiazOrdaz, K.; Kenward, M.G.; Gomes, M.; Grieve, R.;
Stat Med
Missing continuous outcomes under covariate dependent missingness in cluster randomised trials.
Hossain, A.; Diaz-Ordaz, K.; Bartlett, J.W.;
Stat Methods Med Res
Are missing data adequately handled in cluster randomised trials? A systematic review and guidelines.
Díaz-Ordaz, K.; Kenward, M.G.; Cohen, A.; Coleman, C.L.; Eldridge, S.;
Clin Trials
Handling missing values in cost effectiveness analyses that use data from cluster randomized trials
Diaz-Ordaz, K.; Kenward, M.G.; Grieve, R.
Journal of the Royal Statistical Society Series a-Statistics in Society
Comparing diagnostic tests: trials in people with discordant test results.
Hooper, R.; Díaz-Ordaz, K.; Takeda, A.; Khan, K.;
Stat Med
Multilevel models for cost-effectiveness analyses that use cluster randomised trial data: An approach to model choice.
Ng, E.S.; Diaz-Ordaz, K.; Grieve, R.; Nixon, R.M.; Thompson, S.G.; Carpenter, J.R.;
Stat Methods Med Res
See all Karla Diaz-Ordaz's Publications