Looking for associations Ratio measures (relative risk) Rate ratios Risk ratios Prevalence ratios A note about relative risks Standardised incidence and mortality ratios Difference measures (attributable risk) Rate differences Risk…
Disease prevention in public health The scope for preventive medicine Population versus individual risk Strategies for prevention The high-risk strategy The mass strategy The population attributable fraction as a guide…
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…
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…
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?…
