[N119] LEC 3 - Application of Selected Public Health Disciplines: Demography (Part I - Until Worksheet I)

From Ma'am Garcia's PPT and Discussion (Part I - Until Worksheet I)

1. Demography

2. Vital Statistics

3. Epidemiology

What are the three public health disciplines?

Demography

A Public Health Discipline: Science of population

Vital Statistics

A Public Health Discipline: Refer to data on vital events

Births, deaths, marriages

What are included under vital events?

Epidemiology

A Public Health Discipline: Study of the distribution and determinants of health-related states and events in specified populations (CDC, 2012)

“Demos” = “population”

“-graphy” = “describe.”

Demography came from the words “demos” and “-graphien”. What do they mean?

Demography

It refers to the empirical, statistical, and mathematical study of human populations (Bogue, n.d.)

SSD = Size, Structure (or composition), and Distribution

1. Changes in population size

2. Population composition or structure

3. Distribution of population in space

*basically, these are the elements of demography

Demography focuses on 3 observable human events. What are they?

Demography

Under this public health discipline, seeking the reasons for immediate causes of changes in population such as natality, mortality, and migration is important

Migration

• Refers to the movement of people from one place to another

• Demographic process that moves people between places, and so contributes to population change

Natality

Refers to the ratio of the number of births to the size of the population (birth rate)

Mortality

Refers to the number of deaths due to a disease divided by the total population

1. Population size

2. Population composition

3. Population distribution

What are the elements of demography?

Population size

An element of demography: Refers to the number of people living in each place at a given time

PPT

1. Person

2. Place

3. Time

Under population size, what are the three components that you should remember?

Population composition

An element of demography: Refers to all measurable characteristics of the people who make up a given population

ASEM

1. Age

2. Sex

3. Education

4. Marital Status

Under the population composition, give all the mentioned measurable characteristics of a population

Population distribution

An element of demography: Pertains to how people are distributed (i.e., world regions, countries, cities, villages, rural-farm areas, barangays, etc.)

They are important for health workers to make programs specific to the characteristics of a population, because each characteristic of the population can affect the health.

Why do we need to know the size, composition, and distribution of a population?

• Oral Contraceptive Pills or other Reproductive Health Related programs

• Maternal Health Related programs (i.e., antenatal visits, vaccinations, etc.)

If there are more females in a population, what health programs do you think should be prioritized?

• Lifestyle Related programs addressing risky behaviors (e.g., smoking, alcohol drinking, etc.)

• Occupational Health Related programs

  • In a traditional Filipino family, males are most likely the workers or providers

If there are more males in a population, what health programs do you think should be prioritized?

• Vaccination programs, such as EPI

• For medications and deworming

If there are more infants in a population, what health programs do you think should be prioritized?

IPPIS-D (Identify - Plan, Prioritize, and Implement - Study - Describe)

1. Identify and characterize the health problems of a community

2. Plan, prioritize and implement health programs rationally

3. Study determinants or reasons for occurrence of health problems in order to control and prevent them

4. Describe the growth and dispersal of population groups in the past, as well as predict future developments and possible consequences

What are the uses of demography?

CPRR (or CPRs kasi dalawang R)

• Count

• Proportion

• Ratio

• Rate

What are the tools of demography?

Counts

A Tool of Demography: Absolute numbers of a population or any demographic event in a specified area in a specified period

Proportion

A Tool of Demography: A special type of ratio in which the numerator is part of the denominator.

Ratio

A Tool of Demography: A single number that represents the relative size of two numbers

Rate

A Tool of Demography: Occurrence of events over a given interval of time

Rate

A Tool of Demography: Useful in dynamic events

Ratio

A Tool of Demography: Refers to a/b=k

Proportion

A Tool of Demography: Refers to a/a + b = k, where k is 100, it becomes a percentage

Dynamic Events

Time Element (always meron)

What are the keywords under Rate as a tool of demography?

CSRO

• Census

• Sample Surveys

• Registration Systems

• Others

What are the sources of demographic data?

Census

A Source of Demographic Data: Total process of collecting, compiling and publishing demographic, economic and social data pertaining at a specified time to all persons in a country or delimited territory (could be done in barangay or class level as long as everyone is accounted for)

1. De jure method

2. De facto method

What are the two types of Census?

De Jure Method

• The “ur” in de jURe means usual or regular residence :>

A Type of Census (as a source of demographic data): Allocates people to their usual residence, regardless where they are during the census (e.g., Dorming in Manila but will be counted as a person from Navotas); tallies people according to their regular or legal residence

De Facto Method

• The '“f” in de Facto means Fysically Fresent :3

A Type of Census (as a source of demographic data): Allocates people to areas where they are physically present during the taking (e.g., you will be counted as a population in Manila irregardless of where you are from); allocates them to the place where they are enumerated — normally where they spend the night of the day enumerated

Sample Surveys

A Source of Demographic Data: Collecting info only from a subset of a population, which requires a shorter amount of time and lesser resources (cost-efficient)

FALSE; Sample surveys are more preferred than Census, because doing a census is tedious and more resources are needed (like you cannot visit all participants in the whole PH)

TRUE or FALSE: Census are more preferred than Sample Surveys

Registration Systems

A Source of Demographic Data: Include vital registration systems (births, deaths, marriages, etc.); continuous recording of vital events as they occur in the population; systems expensive to maintain which requires regular updating

• Continuing population registries

• Voter’s Registry

• School rosters/enrollment

A Source of Demographic Data: Examples of sources other than census, sample surveys, and registration systems.

2. Sample Surveys

Under what source of demographic data do DOST Surveys belong to?

1. Census

2. Sample Surveys

3. Registration Systems

1. Census

Under what source of demographic data do National Nutrition Surveys belong to?

1. Census

2. Sample Surveys

3. Registration Systems

3. Registration Systems

Under what source of demographic data do TV Registries belong to?

1. Census

2. Sample Surveys

3. Registration Systems

1. Census (Census of population and housing - so far pinakasikat na census)

Under what source of demographic data do PSA’s data collection of population and housing belong to?

1. Census

2. Sample Surveys

3. Registration Systems

NARRA

1. Natural Increase (NI)

2. Absolute change per year (b)

3. Rate of Natural Increase (RNI)

4. Relative Increase (RI)

5. Annual rate of growth (r)

In Measuring Changes in Population Size, what are included?

Natural Increase (NI)

A Measure of Change in Population Size: Difference between the number of births and the number of deaths which occurred in a specific population within a specified period of time (usually one per year)

Natural increase = # of births - # of deaths

What is the formula for the Natural Increase?

914,748 persons (kaya mo na solution niyan, i believe in u my love)

Determine the natural increase of the Philippine population in 2020 given the following data:

• Number of births, 2020 = 1,528,684

• Number of deaths, 2020 = 613,936

456,789 persons were added to the population in 2020 due to natural increase

How would you interpret the Natural increase (NI) if it is equal to 456,789 persons in 2020?

Rate of natural increase (RNI)

A Measure of Change in Population Size: Represents the difference between the number of births and the number of deaths expressed relative to the population size; the difference between the Crude Birth Rate and Crude Death Rate of specific population within a specified period of time

Rate of natural increase = CBR - CDR

What is the formula for the Rate of natural increase (RNI)?

12.91/1000 population (kaya mo na yung solution, malaki ka na)

Determine the rate of natural increase of the Philippine population in 2020 given the following data:

• CBR, 2020 = 18.89/1000 population

• CDR, 2020 = 5.98/1000 population

About 15 persons for every 1000 population were added to the population in 1942 through natural means.

If the computed Rate of natural increase (RNI) is equal to 14.83/1000 population in Japan, 1942 (assuming they also use the same formula and interpretation as us), how would you interpret it?

Absolute change per year (b)

A Measure of Change in Population Size: Measures the average number of people added to the population per year; the numerator is the difference between two population counts while the denominator is the time interval in years between the two census dates

Absolute change per year = (Pt – Po)/t

What is the formula for the Absolute change per year (b)?

78,446 persons per year (summon your ancestors for the solution)

Compute for the absolute change per year of Bulacan given the following data:

• Po= Population, 2010 = 2,924,433

• Pt= Population, 2020 = 3,708,890

There were 50,001 persons added to the population per year from 3067-3077 in Tarlac.

If the computed Absolute change per year (b) in Tarlac is 50,000.997 between the years 3067 and 3077, how would you interpret it?

P_o: Initial/previous/earlier census year

P_t: Latter census year

t: time = P_o: ___________ = P_t: ____________

Relative Increase (RI)

A Measure of Change in Population Size: Actual difference between two census counts expressed in percent relative to the population size during the earlier census

Relative increase = [(Pt – Po)/Po] x 100

What is the formula for the Relative Increase (RI)?

26.82% (nakuha mo rin? slay queen purr 💅)

Compute for the relative increase in the population size of Bulacan Province given the following data:

• Po= Population, 2010 = 2,924,433

• Pt= Population, 2020 = 3,708,890

The increase in the population size in Kwangya between 2020 and 2023 is 45% of its original population.

If the computed Relative Increase (RI) in Kwangya is 44.75% between the years 2020 and 2023, how would you interpret it?

Annual Rate of Growth (r)

A Measure of Change in Population Size: Similar to absolute change and relative increase in the sense that it quantifies the amount of change in the population size during a specified period of time; it takes on the assumption that the population is changing at a constant rate per year.

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BONUS: Click to see the summary of the measures describing the changes in population size

1. Detail desired

2. Time reference

What are the types of estimates in projecting populations?

Detail desired

A Type of Estimate: Include total, aggregate, population subgroups, population with select characteristics

Aggregate population

Under the detail desired type of estimate, this refers to the population per barangay or per municipality; a subgroup or population that share characteristics or concerns (e.g., LGBT+ residents of the same neighborhood)

*the latter is an online definition from LevelUpRN

Time Reference

A Type of Estimate: Include intercensal, post-censal, and projections

Intercensal

Time Reference referring between two population counts

Post-censal

Time Reference referring to immediately after the census data is released

Component Method

A type of method also known as “inflow-outflow” or “balancing equation method”

Mathematical method

A type of method classified depending on the assumption one wishes to make regarding the nature of population growth classified

AGE

1. Arithmetic method

2. Geometric method

3. Exponential method

What are the methods under the mathematical method of projecting population?

Arithmetic method

A Type of Mathematical Method: Assumes that an equal absolute change occurs in the population every year

Geometric method

A Type of Mathematical Method: Assumes that a constant rate of increase or decrease occurs over each unit of time, usually a year

Exponential method

A Type of Mathematical Method: Assumes that a population size is changing continuously, this increase or decrease in population occur at every infinitesimal amount of time

Pt = Po + (B-D) + (I-O)

Component under the type of method used in projecting population

Pt and Po

In Pt = Po + (B-D) + (I-O), these are the population counts at time t and o, respectively

# births occurring during interval o and t

In Pt = Po + (B-D) + (I-O), what does B mean?

# deaths occurring during the same interval

In Pt = Po + (B-D) + (I-O), what does D mean?

# in-migrants between time o and t

In Pt = Po + (B-D) + (I-O), what does I mean?

# out-migrants between time o and t

In Pt = Po + (B-D) + (I-O), what does O mean?

1. Future population (Pt)

2. Past population (Po)

3. Absolute increase per year (b) or Annual rate of growth (r)

4. Time (t)

5. Doubling time (t*)

FAT-P2 (Future - Absolute/Annual - Time — Past - 2x or Doubling)

Give the “unknowns” in the computing various aspects of population estimation using mathematical assumptions

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What is the Future population’s (Pt) arithmetic formula?

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What is the Future population’s (Pt) geometric formula?

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What is the Future population’s (Pt) exponential formula?

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What is the Past population’s (Po) arithmetic formula?

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What is the Past population’s (Po) geometric formula?

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What is the Past population’s (Po) exponential formula?

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What is the Absolute increase per year’s (b) or Annual rate of growth’s (r) arithmetic formula?

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What is the Absolute increase per year’s (b) or Annual rate of growth’s (r) geometric formula?

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What is the Absolute increase per year’s (b) or Annual rate of growth’s (r) exponential formula?

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What is time’s (t) arithmetic formula?

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What is time’s (t) geometric formula?

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What is time’s (t) exponential formula?

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What is doubling time’s (t*) arithmetic formula?

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What is doubling time’s (t*) geometric formula?

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What is doubling time’s (t*) exponential formula?

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For examples, please see the handout on demography at pages 6-12 .

Link: https://drive.google.com/file/d/1YgwKD0uA6YsYVzvgqkWtNjiNkuoJ8b9D/view?usp=sharing

BONUS: Click to view the summary of the formula for computing various aspects of population estimation using mathematical assumptions