Formulas for midterm

Question 1

Incidence rate

Answer 1

of new cases of a disease / # of persons who are at risk of developing the disease

The number of new cases of a disease that occur during a specified period of time in a population at risk for developing the disease;

This is a measure of risk

Question 2

Prevalence

Answer 2

Existing cases / total population

Question 3

Point prevalence

Answer 3

of people with disease at certain point / # of people in total population

“Adults who currently have depression”

Question 4

Period Prevalence

Answer 4

of people with disease during a period of time / # of people in total population during that period of time

“Adults who experienced depression over last 12 months”

Question 5

Cumulative incidence

Answer 5

Number of new cases of disease / number in at-risk population

Question 6

Crude rate

Answer 6

Crude mortality rate; the proportion of a population that dies during the period of interest; does not take into account any other factor such as sex;

Crude mortality rate = # deaths in a given year / reference population (during midpoint of year)

Question 7

Age-adjusted

Answer 7

The frequency of a disease in an age group divided by the total number of persons within that age group during a time period

of deaths in a given year for people of a given age range / # of people in that age range at the midpoint of the year

Question 8

Cause specific mortality rate

Answer 8

(Mortality from a given disease / population size at midpoint of time period) x 100,000

Question 9

Group specific mortality rate

Answer 9

(number of deaths in men / population of men) x 100,000

Question 10

Proportionate mortality ratio (PMR)

Answer 10

(# of deaths due to a specific cause during a time period / total number of deaths during the same period) x 100

Question 11

Case fatality rate

Answer 11

(# of deaths due to disease “X” during a time period / # of causes of disease “X” during a time period) x 100