Module 1 (schedule)
Bias in Observational Studies
(August 23 – September 3)
Instructor: Dr. Ian Dohoo, Professor Emeritus, CVER, AVC, UPEI
Instructor: Dr. Simon Dufour, Professor, University of Montreal
Instructor: Dr. Henrik Stryhn, Professor, CVER, AVC, UPEI
This course covers 2 topics essential for producing valid results from observational data:
– bias (and quantitative bias analysis)
– use of Bayesian methods to incorporate bias correction into the study analyses
In the first section, we will review the three fundamental types of bias (confounding, selection bias, and information bias) including causes of the bias, approaches to preventing the bias and an evaluation of the potential impact these biases could have on study results. Given that not all biases can be prevented, it is important to know how to deal with biases which may affect a study. Two general approaches will be presented. Probabilistic quantitative bias analysis is a post-hoc approach which allows an investigator to apply knowledge about factors which may have biased a study in order to adjust observed estimates of effects (eg odds ratios) to remove the bias effects. While it does allow for adjustment for multiple biases and for uncertainty in bias parameters estimates, probabilistic quantitative bias analysis is usually applied to models that can be summarized by a 2×2 table.
Bayesian methods allow for incorporation of bias parameters directly during the analysis phase and, consequently, can be applied to more complex models. For instance multivariable logistic regression model (ie models with more than one predictor, including continuous predictors), mixed models (ie models with random effects), etc can be run with these. Using the Bayesian methods allows an investigator to compute unadjusted and bias-adjusted point estimate and 95% CI that will, hopefully, be closer to the true counterfactual effect. At the very least, it would allow for estimating the biases direction and magnitude.
The course is planned to run all days 12 – 4 pm ET during Aug 23 – Sep 3, excluding the weekend. Online participation will be possible, and in-person participation may be possible as well.
Software used will be a combination of spreadsheets (provided) and R programs. Participants will need to have some proficiency in R (primarily for the Bayesian analyses). Guidance in developing this proficiency will be provided.
Module 2 (schedule)
Applied Concepts of Bayesian Risk Assessment
in Animal Health and Food Safety
(September 8 – 21)
Instructor: Dr. Javier Sanchez, Professor, CVER, AVC, UPEI
This course will introduce the concepts of probabilistic risk analysis (PRA) using a Monte Carlo and Bayesian frameworks. PRA is an analysis of the frequency and consequences of unwanted events in a system. This type of analysis relies on probabilistic (i.e., predictive) models and associated data. Participants will compare Monte Carlo with Bayesian based methods applied to risk assessment. Bayesian inference techniques are useful in situations where empirical evidence is not available because, unlike frequentist statistical methods, the Bayesian paradigm incorporates this type of information. Furthermore, from a practical perspective, Bayesian techniques, which represent uncertainty with probability distributions, provide a ready framework for the propagation of uncertainties through the risk models.
Online participation will be possible, and in-person participation may be possible as well.
At the end of the workshop the participants should:
- Be familiar with Monte Carlo and Bayesian risk assessment frameworks
- Conduct basic Monte Carlo simulations
- Understand components of a Bayesian risk assessment model
- Develop posterior distributions from common Bayesian models in Excel and OpenBUGS
- Apply these concepts to their own risk models.
The online registration for Module 1 is full. We accept people for a waiting list in case there are any cancellations.
For Module 2, the following registration fees apply (amounts are in $Cdn and include taxes and administration fees):
Module 2 – Applied Concepts of Bayesian Risk Assessment
in Animal Health and Food Safety
Participant Course Fees Student* 550 Non-student 1000
*Proof of enrollment in a graduate program at a university (not necessarily UPEI) required.
To register for Module 2 of the Epi on the Island 2021 summer courses, please click on the following Eventbrite logo:
For further inquiries, including requests to be put on a waiting list, please contact Jenny Yu at email@example.com.