Muddied waters: the challenge of confounding
An example of confounding: is alcohol a risk factor for lung cancer? Characteristics of a confounder The effects of confounding How can we tell if an association is confounded? When…
Outbreaks, epidemics and clusters
Outbreaks, epidemics and clusters Epidemiology of infectious diseases A causal model The infectious agent The host Transmission The environment Non-infectious clusters and outbreaks Outbreak management and investigation Management of outbreaks…
Who sank the boat? Association and causation
What do we mean by a cause? Some definitions Association versus causation Evaluating causation Temporality Strength of association Consistency Dose–response relationships Biological plausibility Specificity Pulling it all together An example:…
Surveillance: collecting health-related data for epidemiological intelligence and public health action
The scope of surveillance Why conduct surveillance? Surveillance essentials Defining a case for surveillance purposes Collection of surveillance data Analysis of surveillance data Evaluation of surveillance systems Types of surveillance…
Epidemiology and the public’s health
From: www.Cartoonstock.com Challenges So what have we learned from this? The totality of evidence indicates that beta-carotene is a good marker of (and part of) a beneficial diet, but is…
Heads or tails: the role of chance
Random sampling error Statistical significance: could an apparent association have arisen by chance? Confidence intervals The relationship between p-values and confidence intervals Power: could we have missed a true association?…
Assembling the building blocks: reviews and their uses
What is a systematic review? Identifying the literature Publication and related biases Study inclusion and exclusion Appraising the literature Summarising the data Graphical display of results Assessing heterogeneity Meta-analysis Pooled…
Reading between the lines: reading and writing epidemiological papers
The research question and study design Internal validity The study sample: selection bias Example 1:case–control studies of blood transfusion and Creutzfeldt–Jakob disease Example 2:a case–control study of oesophageal cancer and…
Cross-sectional studies
Chapter 5Cross-sectional studies 5.1 Purpose Cross-sectional studies are usually the simplest observational studies to conduct and analyse. They are often used to describe (summarise) the characteristics, habits, or opinions of…
Outcome measures, risk factors, and causality
Chapter 2Outcome measures, risk factors, and causality This chapter describes the three fundamental types of measurements used in observational studies and how data based on each type are summarised and…
