@TexasDemography

Basic Demographic Measures

Population Growth Forum

Region 10 Service Center

Dallas, Texas

July 14, 2016

Ninth

Eighth

Seventh

Sixth

Fifth

Fourth

Third

Second

First Billion

Number of years to add each billion (year)

All of Human History (1800)

130 (1930)

30 (1960)

15 (1975)

12 (1987)

12 (1999)

14 (2013)

14 (2027)

21 (2048)

Sources: First and second billion: Population Reference Bureau. Third through ninth billion: United Nations, World

Population Prospects: The 2004 Revision (medium scenario), 2005.

World Population Growth, in Billions

Billions

0

1

2

3

4

5

6

7

8

9

10

1950 1970 1990 2010 2030 2050

Less Developed Regions

More Developed Regions

Source: United Nations, World Population Prospects: The 2004 Revision (medium scenario), 2005.

Growth in More, Less Developed Countries

Population Increase and Growth Rate, Five-Year Periods

80

8783

7976 76 75

72

0

10

20

30

40

50

60

70

80

90

1980-

1985

1985-

1990

1990-

1995

1995-

2000

2000-

2005

2005-

2010

2010-

2015

2015-

2020

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

Net population added per year Annual population growth rate

Mill

ion

s

Pe

rce

nt in

cre

ase

pe

r ye

ar

Source: United Nations, World Population Prospects: The 2004 Revision (medium scenario), 2005.

Trends in Population Growth Worldwide

Thomas Malthus

Essay on the Principle of Population

• Relationship between population and

resources

• Population growth threatened prosperity

because it inevitably outran increases in food

supplies

• agricultural production grew

arithmetically, increasing by the same

amount over 25 years

• population grew geometrically, doubling

every 25 years

Population Clock

Modeling population and its consequences

Some models show population growth leading to resource depletion, which can result in declining food production, industrial output, and population.

Increasing our carrying capacity

Technology has allowed us to raise Earth’s carrying capacity for our species time and again.

Tool-making, agriculture, and industrialization each enabled humans to sustain greater populations.

Arithmetic Growth

population increases by a constant number of

persons for each period

arithmetic growth entails constant increments

Geometric Growth

Geometric growth entails ever larger increments.

Population increments become larger because increases are self-reinforcing

“compound interest”

Exponential Growth

Exponential growth refers to the situation where growth

compounds continuously - at every instant of time.

Annual Growth Rates

Logistic growth

“universal law of population growth”

S-shaped trend is a more realistic depiction of long-run national or

global population growth than straight lines or exponential curves

y = 406819e0.2695x

0

5,000,000

10,000,000

15,000,000

20,000,000

25,000,000

30,000,000

35,000,000

40,000,000

45,000,000

50,000,000

1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

Population Expon. (Population)

Extrapolation of Texas Population Using Historical Data (1850-1990) -Exponential

0

5,000,000

10,000,000

15,000,000

20,000,000

25,000,000

30,000,000

35,000,000

40,000,000

45,000,000

50,000,000

1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

Population Log. (Population)

Extrapolation of Texas Population Using Historical Data (1850-1990) - Logistic

y = 1E+06x - 3E+06

0

10,000,000

20,000,000

30,000,000

40,000,000

50,000,000

60,000,000

1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

Population Linear (Population)

Extrapolation of Texas Population Using Historical Data (1850-1990) - Linear

Extrapolation of Texas Population Using Historical Data (1850-1990) -Polynomial

y = -54.89x5 + 3104.9x4 - 54032x3 + 422923x2 - 795476x + 708676

0

10,000,000

20,000,000

30,000,000

40,000,000

50,000,000

60,000,000

1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

Population Poly. (Population)

Extrapolation of Texas Population Using Historical Data (1850-1990) -Polynomial

y = -54.89x5 + 3104.9x4 - 54032x3 + 422923x2 - 795476x + 708676

0

10,000,000

20,000,000

30,000,000

40,000,000

50,000,000

60,000,000

Population Poly. (Population)

Analyzing Growth

• Absolute change

• Percent change

• Average annual increase

• Arithmetic growth rate

Geometric Growth

• Estimating intercensal numbers, or projecting future population, assuming that the growth rate remains constant (growth rates usually vary through time)

Geometric Growth

Growth and Replacement

Age structure: Age pyramids

Canada (left) has a much slower growing population than does Madagascar (right).

Age structure: “Graying populations”

Demographers project that China’s population will become older over the next two decades.

Factors affecting population growth rates

Population growth depends on rates of birth, death, immigration, and emigration.

(birth rate + immigration rate)

– (death rate + emigration rate)

= population growth rate

Natural rate of population change

Change due to birth and death rates alone, excluding migration

Is often expressed in % per year

China’s natural rate of change has fallen

China’s rate has fallen with fertility rates. It now takes the population 4 times as long to double as it did 25 years ago.

Global growth rates have fallen

The annual growth rate of the world population has declined since the 1960s.

(But the population size is still rising)

Fertility rates affect population growth rates

Total fertility rate (TFR) = average number of children born per woman during her lifetime

Replacement fertility = the TFR that keeps population size stable

For humans, replacement fertility is about 2.1.

Total fertility rates by region

African nations have the highest TFRs.

European nations have the lowest TFRs.

INTERPOLATION OF POINT DATA

• Interpolation - inferring intermediate values in a given series of data by use of a mathematical formula or a graphic procedure.

• Extrapolation - inferring values that go beyond the given series of data by use of a mathematical formula or a graphic procedure.

Summary measures

• Sex ratios

• Dependency ratio

• Child dependency ratio

• Aged dependency ratio

• Economic dependency ratio

• Aging index

• Caretaker ratio

Central age – single year digits

• Mean - sum of values

number of values

• Mode - most frequently occurring value or group

• Median -middle value in a set of numbers arranged in ascending or descending order

Median age

• The median is preferred to the mean because of the marked skewness of the age distribution

• The calculation of mean is often complicated by open-ended age groups (e.g. 80+)

Age pyramids

• Gives a detailed picture of the age-sex structure of a population

• Consists of bars representing age groups in ascending order from lowest to highest pyramided on one another

• Bars are generally by single or 5-year age groups• Number (or percentage) of persons in an age group is

indicated by length of its bar from central axis• Males on left side; females on right side• Pyramids with absolute numbers show differences in overall

sizes of total populations and in number at each age• Percent pyramids show relative differences in population

size at each age-sex group

Age structure of Finnish population in 1917 and 2006

http://www.stat.fi/tup/suomi90/joulukuu_en.html

Texas Population Pyramid by Race/Ethnicity, 2010

200,000 150,000 100,000 50,000 0 50,000 100,000 150,000 200,000

Under 1 year

5 years

10 years

15 years

20 years

25 years

30 years

35 years

40 years

45 years

50 years

55 years

60 years

65 years

70 years

75 years

80 years

85 years

90 years

95 years

100 to 104 years

NH White Male Hispanic Male NH Black Male NH Asian Male NH Other Male

NH White Female Hispanic Female NH Black Female NH Asian Female NH Other Female

Source: U.S. Census Bureau 2010 Decennial Census, SF1

Texas non-Hispanic White and Hispanic Populations by Age, 2010

0

50000

100000

150000

200000

250000

Un

der

1 y

ear

4 y

ears

8 y

ears

12

yea

rs

16

yea

rs

20

yea

rs

24

yea

rs

28

yea

rs

32

yea

rs

36

yea

rs

40

yea

rs

44

yea

rs

48

yea

rs

52

yea

rs

56

yea

rs

60

yea

rs

64

yea

rs

68

yea

rs

72

yea

rs

76

yea

rs

80

yea

rs

84

yea

rs

88

yea

rs

92

yea

rs

96

yea

rs

10

0 t

o 1

04

…

Po

pu

lati

on

Age

White (non-Hispanic)

Hispanic

Source: U.S. Census Bureau 2010 Decennial Census, SF1

Contact

Office: (210) 458-6530

Email: Lloyd.Potter@utsa.edu

Internet: demographics.texas.gov

Lloyd Potter, Ph.D.

@TexasDemography