Week 2 Quantifying disease in populations Part 1 Flashcards
Define counts as a quanitative measure
The simplest measure of all, the number of cases of a disease or other health phenomenon
What does a ratio consist of?
A numerator and a denominator
What are three ways a ratio can be expressed?
Numerator and denominator with a colon e.g 4:2
As a fraction eg 4/2
Completing the division and expressing as decimal form 2.0
What is a proportion?
A type of ratio in which the numerator is part of the denominator
Allow description of an event relative to the group
How can proportions be expressed?
As a percentage
Or as a decimal between 0 - 1
What is a rate?
A type of ratio in which the numerator consists of the frequency of a disease and the denominator involes a measure of time
How are rates usueful?
provides information about the speed of development of a disease
What are the 3 elements that make up a rate?
Number of people affected by condition
Size of population
Time period during which the event occured
What is prevalence?
The existing cases of a disease at a point in time
What are the two types of prevalence?
Point prevalence (single point in time)
Period prevalence (over period of time)
