
Medmastery: PPV and Specificity
Franz Wiesbauer looks at the impact of specificity and sensitivity on positive predictive value (and thus validity of a test) and why one has a bigger impact than the other.

Franz Wiesbauer looks at the impact of specificity and sensitivity on positive predictive value (and thus validity of a test) and why one has a bigger impact than the other.

Franz Weisbauer explains how to calculate mortality rates for various subgroups, proportionate mortality, and why proportionate mortality is not a measure of risk.

Franz Wiesbauer explains how to express prognosis with the help of life tables and why this is essential to understanding Kaplan Meier curves.

Franz Wiesbauer looks at how a doctor can work out the probability of disease when confronted with a positive or a negative test result and how the prevalence of a given disease affects this probability.

John Snow (1813-1858) was one of the first anaesthetists – he even chloroformed Queen Victoria! – but today he is famous for his investigation of the 1854 Broad Street cholera outbreak in Soho, London. By mapping the cases of cholera…

John Snow (1813-1858), English physician. Pioneer of anaesthesia and epidemiology. Defined etherization stages and traced cholera outbreaks to contaminated water in London.