# (F) Rates and Ratio Flashcards

How would we know if a person is healthy or not?

- History
- Physical/Laboratory examination

How would we say if a country/community is healthy?

- Using various indices (mortality rates, morbidity rates, fertility rates)
- Indices of health to be checked

Tools for Epidemeiology

absolute numbers of a population or any demographic event occurring over a specified period, area, and time

Counts

Tools for Epidemeiology

A single number that represents the relative size of two numbers

Ratio

in this tool of epidemiology you have numerator and denominator (2 numbers relating w/ each other)

Ratio

Tool of Epidemiology

describe the relationship between two (2) numerical quantities or measures of events

without taking particular consideration of their entity

Ratio

Tool of Epidemiology

These quantities need not necessarily represent the same entities

Ratio

unit of measure must be the same for both numerator and denominator of the ratio

What tool of epideiomology?

Doctor-Patient Ratio

Ratio

nasa tanong na nga bobo kaba

Tool of Epidemiology

Special type of ratio in which the numerator is part of the denominator

Proportion

T or F

Proportions are all ratios but not all ratios are proportions

True

Tool of Epidemiology

Measures the amount of change (no. of new events) in a given period of time

Rates

Tool of Epidemiology - T or F

In Vital Statistics, a rate shows the relationship between a vital event and those unexposed persons to the occurrence of said event, within a given area and during a specified unit of time.

F

EXPOSED PERSONS

Tool of Epidemiology - T or F

It is evident that the persons experiencing the event (the numerator) must come from the total population exposed to the risk of same event (the denominator).

T

Type of Rates

If the actual number of events is related to the whole population.

Crude Rate

Denominator is the whole population

Types of Rate

If the events are related to specific subgroups of the population

Specific Rate

Type of Rates

**Fictitious** **summary** **rates** constructed to permit fair comparison between population groups differing in some important characteristic

Adjusted Rates

what type of rate is used when comparing a devloping country to a develop one, the aim is to provide a EQUAL FOOTING

Adjusted Rate

Fertility Rates

Measures how fast the population increases through the process of natality (birth)

Crude Birth Rate (CBR)

Fertility Rates

measure of one characteristic of the natural growth or increase of a population

Crude Birth Rate (CBR)

Fertility Rates

Relates the number of live births, which occurred in a specified population during a specified time interval, to the total population.

Crude Birth Rate (CBR)

IF u see this card

review the formula for crude rate

Total no. of live births in a given year/Total population as of July 1 (same yr)

Crude Birth Rate

Since the population size changes during the year, what population are used in the denominator?

midyear population→ July 1

Fertility Rate

More specific as this studies only the subgroup which in a fertility age group – actually giving birth in the women reproductive group

General Fertility Rate (GFR)

Fertility Rate

more appropriate measure of fertility would be one which relates the number of births to the segment of the population who is actually at risk of giving births

General Fertility Rate (GFR)

review the formula for General Fertility Rate

ge

No. of reported live births/midyear population of women in the reproductive years (15-44 or 49 y.o.)

Enumerate the Fertility Rates

- Crude Birth Rate
- General Fertility Rate
- Age-Specific Birth Rates
- Child Women Ratio

if u see this card

review the formula for age-specific birth rates and Child women ratio

age-specific birth rates= births registered during year (specified age interval of women)/mid year population of women in same age group

child-women ratio= no. of <5y.o./midyear population of women 15-44

What are the 2 mearuse for morbiditiy rates?

- Measure of Incidence
- Measures of Prevalence

when it is measure of incidence under morbidity, what study it encompasses and what type are the cases

Cohort study, and new cases

when it is measure of Prevalence under morbidity, what study it encompasses and what type are the cases

Cross-sectional study, and existing cases

Morbidity Rates

Measures the number of new cases developing during a period of time.

Incidence

Morbidity Rates

new cases come from a population which is disease-free at the beginning of an observation period. This disease=free population is the population at risk.

Incidence

Morbidity Rates

a measure of the average risk or the average probability of developing an illness in a disease-free individual

Cumulative Incidence

study the formula for cumulative incidence

ge

No. of new case of a disease during a specified time/No. of disease-free individual at the beginning of the period

Morbidity Rates - Cumulative Incidence

The numerator generally refers to the

first occurrence of the illness

Morbidity rate, CI - T or F

The period of observation should be explicitly stated since the longer the observation period, the higher the CI will be

True

Morbidity Rate

a special kind of Cumulative Incidence where the period of observation is limited as in an epidemic.

Attack Rate

Morbidity Rate, CI - T or F

Requires that all non cases be followed up for the entire duration of the follow up period

True

diko magets sensha, pero t daw sabi ni maam

Morbidity Rate, CI - T or F

Conditional on dying first of other diseases during the observation period

F - NOT DYING FIRST

Morbidity Rate

an estimate of the average rate of disease occurrence in a population.

Incidence Density (ID) or Incidence Rate (IR)

Morbidity Rate

This is also called FORCE OF MORBIDITY or HAZARD RATE.

Incidence Density (ID) or Incidence Rate (IR)

Morbidirt Rate

The period of observation for the entire group may not be explicit BUT the time of follow-up for each individual is taken into consideration in the denominator which is measured in PERSON-TIME

Incidence Density or Incidence Rate

ID or IR

observation is the sum of the period of observation for each individual in the cohort.

Person- Time

review the illustration for person time

ge

Morbidity Rate, IR or ID - T or F

SOMETIMES the length of observation may not be known for each subject as when following up big population groups

True

Morbidity Rate, IR or ID - T or F

Person-time of observation is computed as the product of the average sample size and the length of follow-up

F - POPULATION SIZE

check the illustration para mas magets

what is the assumption that is wanted in ID or IR

that there is no drastic change in the size and structure of the population.

Morbidity Rate

Measures the number of existing cases at a point in time relative to a population at the time.

Prevalence

Morbifity Rate, Prevalence

Particular point in time

Point Prevalence

Morbifity Rate, Prevalence

This means the probability of an individual being a case at a point in time, not of developing disease.

Point Prevalence

Morbifity Rate, Prevalence

This measure is generally used in health planning to quantify needs or demands for services.

Point Prevalence

review the steps for point prevalence

go bro

no. of existing cases at a point in time/total population at that point in time

what can be also measured in Point prevalence?

Residuals of ilnesses

Morbidity Rate, Prevalence

Segment in time

Period Prevalence

Morbidity Rates, Prevalence

This combines the prevalence at the beginning of a period (point prevalence) plus all the cases that will develop during the period (cumulative incidence).

Period Prevalence

Relationship of Incidence and Prevalence

T or F

All cases start at Prevalence

F - starts at INCIDENCE