Why screen? The disease process Screening versus case-finding The requirements of a screening programme The disease The screening test Test quality: sensitivity and specificity Test performance in practice: positive and…
Sources of error in epidemiological studies Selection bias Some specific sources of selection bias Volunteers Low response rates Loss to follow-up Ascertainment or detection bias The healthy-worker effect Control of…
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 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…
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:…
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…
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…
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?…
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…
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…
