Statistical Thinking

This blog is devoted to statistical thinking and its impact on science and everyday life. Emphasis is given to maximizing the use of information, avoiding statistical pitfalls, describing problems caused by the frequentist approach to statistical inference, describing advantages of Bayesian and likelihood methods, and discussing intended and unintended differences between statistics and data science. I’ll also cover regression modeling strategies, clinical trials, drug evaluation, medical diagnosis, and decision making.

Frank Harrell

Frank Harrell

Professor of Biostatistics

Vanderbilt University

Biography

Frank Harrell is a Professor of Biostatistics in the School of Medicine at Vanderbilt University. His research interests include statistical modeling, semiparametric ordinal models, predictive models and model validation, longitudinal models, Bayesian statistics, Bayesian clinical trial design, clinical trial design, analysis, and reporting, statistical computing, statistical graphics, reproducible research, drug development, medical decision making and diagnostic research, health services research, cardiology, COVID-19 therapeutic clinical trial design, and teaching.

Interests

  • Statistical modeling
  • Bayesian statistics and study design
  • Predictive modeling and model validation
  • Semiparametric ordinal models
  • Longitudinal models
  • Biomedical research
  • Medical decision making
  • Medical diagnostic research
  • Statistical computing, graphics, and reproducible research methods
  • Cardiology
  • Clinical trial design, analysis, and reporting
  • COVID-19 therapeutic clinical trials
  • Health services research
  • Drug development

Education

  • PhD in Biostatistics, 1979

    University of North Carolina

  • BS in Mathematics, 1973

    University of Alabama in Birmingham

Skills

Biostatistics

R

Biomedical Research

Teaching

This is a free web course in introductory and intermediate biostatistics. Details are on the course web page.

Regression Modeling Strategies

I teach the BIOS7330 Regression Modeling Strategies course in the Biostatistics Graduate Program at Vanderbilt University in the spring semester. The course web page is here. I teach a 4-day virtual version of this course each May. Registration information for the short course may be found here.

Master of Science in Clinical Investigation Biostatistics II

I co-teach this course at Vanderbilt each February for postdoctoral medical and surgical fellows and junior faculty in the MSCI program.

Recent Posts

R Workflow

This article outlines analysis project workflow found to be efficient in making reproducible research reports using R with Rmarkdown and now Quarto. I start by covering the creation of annotated analysis files and running descriptive statistics on them with goals of understanding the data and the quality and completeness of the data. Functions in the Hmisc package are used to annotate data frames and data tables with labels and units of measurement and to produce tabular and graphical statistical summaries. Several examples of processing and manipulating data using the data.table package are given. Finally, examples of caching results and doing parallel processing are presented.
Last updated on 2022-05-19 0 min read

Resources for Ordinal Regression Models

This article provides resources to assist researchers in understanding and using ordinal regression models, and provides arguments for their wider use.
Last updated on 2022-05-05 0 min read

Decision curve analysis for quantifying the additional benefit of a new marker

This article examines the benefits of decision curve analysis for assessing model performance when adding a new marker to an existing model. Decision curve analysis provides a clinically interpretable metric based on the number of events identified and interventions avoided.
Last updated on 2022-04-12 0 min read

Equivalence of Wilcoxon Statistic and Proportional Odds Model

In this article I provide much more extensive simulations showing the near perfect agreement between the odds ratio (OR) from a proportional odds (PO) model, and the Wilcoxon two-sample test statistic. The agreement is studied by degree of violation of the PO assumption and by the sample size. A refinement in the conversion formula between the OR and the Wilcoxon statistic scaled to 0-1 (corcordance probability) is provided.
Last updated on 2022-04-20 0 min read

Longitudinal Data: Think Serial Correlation First, Random Effects Second

Random effects/mixed effects models shine for multi-level data such as measurements within cities within counties within states. They can also deal with measurements clustered within subjects. There are at least two contexts for the latter: rapidly repeated measurements where elapsed time is not an issue, and serial measurements spaced out over time for which time trends are more likely to be important.
Last updated on 2022-03-16 7 min read
See all posts

Projects

Recent & Upcoming Talks

Controversies in Predictive Modeling, Machine Learning, and Validation

This talk covers a variety of controversial and/or current issues related to statistical modeling and prediction research. Some of the …
2022-01-21 00:00
Code Slides Video

Longitudinal Ordinal Models as a General Framework for Medical Outcomes

Univariate ordinal models can be used to model a wide variety of longitudinal outcomes, using only standard software, through the use …
2021-12-18 00:00 Kings College London/Virtual
Slides Video

Modernizing Clinical Trial Design and Analysis to Improve Efficiency & Flexibility

This presentation covers several ways to make clinical trials more efficient and to reduce the chance of ending with an equivocal …
2021-11-16 00:00
Slides Video

Musings on Statistical Models vs. Machine Learning in Health Research

Video
Health researchers and practicing clinicians are with increasing frequency hearing about machine learning (ML) and artificial …
2021-05-31 00:00
Slides Video

Sequential Bayesian Designs for Rapid Learning in COVID-19 Clinical Trials

Continuous learning from data and computation of probabilities that are directly applicable to decision making in the face of …
2020-11-25 00:00
Code Slides Video
See all talks

Topics

accuracy-score backward-probability bayes big-data bioinformatics biomarker bootstrap change-scores classification collaboration conditioning covid-19 data-reduction data-science decision-making design diagnosis dichotomization drug-evaluation EHR endpoints evidence forward-probability generalizability graphics hypothesis-testing inductive-reasoning inference judgment likelihood logic machine-learning measurement medical-literature medicine metrics multiplicity observational ordinal p-value personalized-medicine posterior precision prediction principles prior probability r RCT regression reporting reproducible responder-analysis sample-size sensitivity sequential specificity subgroup survival-analysis teaching validation variability 2017 2018 2019 2020 2021 2022

Contact

Statistical Thinking News

Statistical Thinking News is a companion site for news and opinions on data analysis and statistical modeling, prediction, statistical computing, research design and interpretation, clinical trials, and research integrity. It is updated at least weekly.

Datamethods

datamethods.org is a discussion site where data methodologists meet each other and subject matter experts including clinical trialists and clinical researchers. Its development is documented here. Datamethods is provided by the Department of Biostatistics, Vanderbilt University School of Medicine.

I have written some short articles on the site, listed below.