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RESOURCE

| a MANUAL

' BSPOP

UNITED STATES POPULATION STUDY

Developed by: James Friedland, General Douglas MacArthur High School Levittown, New York Support Material By:

James Friedland

Programmed By:

James Friedland Stuart Hollander, State University of New York Stony Brook, New York

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HUNTINGTON TWO COMPUTER PROJECT Copyright © 1973, State University of New York

| y 13 June 1973 -_ | |

The work of the Huntington Two Computer Project is partially supported by the National Science Foundation, Grant GW-5883.

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USPOP

RESOURCE MANUAL

Table of Contents

Why Use USPOP ® e ® e e e * e a7 v ° ® ® a & °

Backgrounds on Human Population Study... .

History of haps tase ne a See eee re Fertsisety sess ee ee Re ee Ge i ae Birth Wstrtherion se a See Ca tas ge Bee ee Bee ROtio Of OLispring: 4 45.5 6s 3h 8 Mee ALi ty a Se Se mae DESTES ONC L OR 6h 6 NEE

POS Te oe aS ee ee ee See

A. B.

Explanation of Program Inputs. ...... AGG. Crone Sample Bene «ao 6S 6 ee ee

The USPOP Model . s e t + _* e . e e e ° e a LJ

ADOUE RO OGG) oa Se Se UBPGPr eine ce OMUEES 5 5 oF he we ee Additional Considerations and Assumptions. USPOr TASTSGG. 5 3k ee Sa ae ee SCOSTEM VET OULOS Ge 6 ae SS Maceeine CSrer 3 es eS ee eee

Additional Student Projects Using USPOP ...

Supplementary Readings and Films. ......

. 30

I. WHY USE USPOP

The current growth rate of the world's population is about 2% per year; while this rate may seem small enough, the U. S. National Academy of Sciences has projected that if this growth rate had prevailed since the time of Christ, there would now be 100 persons per square foot of the earth's surface. Given today's larger population, a continuing growth rate of 2% per year would lead to the same unbelievable population densities in only a few centuries. Clearly, this rate of population growth cannot be maintained indefinitely.

This idea of a population threat was not well defined for the average person even ten years ago; today the population explosion is a deep and troub- ling concern for many grade school children. For this reason, an analytical approach to the problem of population growth and control is as important as it is appropriate in secondary education today.

In general, the teacher is as restricted in the study of population problems as the student. The problem of human population growth, when fully analyzed, is a highly complex mathematical phenomenon; not only are such obvious factors as birth rate and death rate important, but the sex ratio of offspring, time of first birth, and differential mortality also play a critical role. For example, while the United States is worrying about overpopulation, countries such as France worry about underpopulation. In the case of these two countries, the main difference lies in the age structures of their respective populations. In France about 30% of the population is over 50, so that a substantial number of women are past reproductive age. This results in fewer births per person and declining population.

With these ideas in mind, the HUNTINGTON TWO PROJECT embarked on the development of a human population model that could be used in the classroom and as an educational tool, as well as in the laboratory. USPOP is based on a model quite close to that used by U. S. Government demographers in their population projection work. Several simplifying assumptions had to be made since we were restricted in the degree of complexity we could achieve on a so-called minicomputer; but comparisons of USPOP and government projections indicate that errors due to these assumptions are relatively small.

USPOP has been developed primarily to provide the student with labora- tory experiences, or to facilitate individualized learning about population factors. To this end, the STUDENT MANUAL contains suggested investigations. The Manual covers the effects of fertility, mortality, and birth distribution | on both population size and age structure. All these investigations are basic in both approach and necessary student skills. More advanced investigations may be found in the RESOURCE MANUAL. |

No teacher is likely to ask his or her students to carry out all five of the laboratory investigations. These have been included to allow the teacher to choose investigations that best complement the course of study, or to accommodate the teacher who feels it important to have each group of students tackle a unique problen.

Each investigation in the STUDENT MANUAL examines the effect of a single variable. The student is given an introductory reading that explains USPOP in general and his problem in particular. He is then given a suggested procedure that may be used to solve the problem. These suggestions are quite general, however, and depending on the skill of your class in biological investigation, you may decide to supplement them with additional instructions found in the TEACHER MANUAL. After completion of the investigation, the student is presented with several questions that can be used to evaluate his or her achievement. Sample answers to these questions are aiso supplied in. the TEACHER MANUAL.

II. BACKGROUNDS ON HUMAN POPULATION STUDY

A. History of Demo graphy

Demography, the study of populations, existed long as a discipline before it received its current name. In 1855, Builliard coined the term from the Greek word "demos" meaning people. Demography had its genesis in the very earliest census gathering. The need to know the size and nature of the population grew as government became more centralized. There is evidence to indicate that an extensive census was taken during the reign of King David (about 1000 B.C.), and both the Greeks and Romans clearly used census data in their planning.

The Romans were concerned with population planning to such an extent that they attempted to legislate an increase in birth rate by denying childless women the right to wear jewelry. It should be noted that they met with very little success.

Modern periodic census-taking started in the year 1666 with a Cana- dian census. With each passing year the mound of data has grown; had demography failed to make use of developing statistical techniques, census- taking would have soon become impossible. Demography was one of the first biological fields to make use of quantitative methods, and doing census work today is practically synonymous with computer technology, because of the vast amounts of information that have to be processed in order to ad- minister to the complex needs of the population.

It is not enough to know what has taken place, however; it is often necessary to plan projects many years into the future. This need brought about a second phase of human demography -- population projection. Natur- ally, early projection techniques were crude, The Greeks attempted to model the growth of population considering such facts as birth and immi- gration versus mortality and emigration. By the late 1500's, certain Italian demographers had begun to study the role of environmental limita- tions. Today demographers have developed a complex set of variables to describe the behavior of population.

oo -—

Compared with early population projections, today's work seems accurate indeed. Yet, for all the statistical information available, no definite answer as to future population is ever possible; there are always contin- gencies which cannot be predicted. For this reason, government demographers never make a single projection. Entire series of projections are made, with a different set of assumptions for each projection. In this way, the like- lihood of having a projection which approximates reality is increased.

In any project many variables have to be evaluated. Some of the most important variables are fertility, birth distribution, sex ratio, and mor- tality. These four variables interact with a fifth: age distribution. ©

Bas Fertility

Fertility can be thought of as the number of live births the average woman can be expected to have over her entire reproductive life span. This term is more biologically precise than birthrate (which is in units of births per 1000 population), because it is unaffected either by the sex or age dis- tribution of the population.

Fertility varies from country to country and from time to time. Under- developed countries tend to have high fertility, as well as high mortality rates; fertility as high as 6-10 children per female is not at all uncommon. Industrialized countries, on the other hand, have both lower fertility and lower mortality rates. Fertility in industrialized countries is generally between 2.0 and 4.0.

Fertility in the United States has varied greatly over the past 50 years, as shown in the chart below. Variations in fertility have been correlated with both the social and economic conditions in the country.

Year Fertility (children per female)

1920 3:3 1925 3.0 1930 2.5 1935 3.3 1940 23 1945 2.5 1950 34 1955 3.6 1960 ce 1965 2.9 1970 2.45 1972 2.1 estimated

During the depression in the 1930's, fertility was low and this low pattern continued throughout World War II. Starting in the late 40's and Ba early 50's, fertility has shown the effects of the post-war baby boom. : Fertility continued to grow throughout the 50's into the early 60's as former servicemen continued to expand their families. By the late 60's, however, these families passed out of the reproductive pool and fertility again decreased.

Others have tried to explain this fertility shift in economic terms. The 30's and the war years were periods of economic uncertainty as well as low fertility. While many economists predicted serious economic trou- bles for the United States in the post-war years because of the problems of adjusting to a peace-time economy, the problems never developed. The 1950's were a time of great economic growth; fertility and average family size also grew throughout this period. Starting with the 70's, the economy again became uncertain, and at this time fertility again showed a dip.

Fertility today is currently at a level very near that recorded during the midst of the depression. Opinion as to why this should be so is divided. Some see this change as a permanent shift in attitude about family size in women entering the reproductive pool, while others interpret this drop in fertility as an effect of an uncertain economy, saying that fertility has dropped because many women are delaying their families. In either case, the next few years should tell if fertility will remain low or swing upward again,

Ga Birth Distribution

>_4

When children are born to a woman is often as important as the number of children, Since we used the term fertility to describe the average number of offspring, we may describe birth distribution in terms of the fraction of fertility expressed for each year of the woman's reproductive period. 7

Just as fertility has varied in the United States' recent history, so has birth distribution.

TABLE 2 PER CENT FERTILITY IN EACH 5-YEAR PERIOD

AGE 1970 1965 1960 1955 1950 1945 1940 - 10-14 2 2 at o wl = ak 20-24 33.8 BE Ae Ke Pes 33.6 73 ee 27.9 2945 30-34 14.7 16.2 15.4 16.3 16.7 20.1 18,1 35-39 6.6 709 7.8 8.3 8.6 LiD 10.0 40-44 i.s Led 2k a 2.4 ee 3.4 45-49 es 5 = a 52 2 4

This chart shows that women today are having their children earlier. There appear to be two reasons for this effect. First, women today are having fewer children, so we would naturally expect a greater percentage of their offspring to be born during these women's earlier reproductive years. Secondly, there is the effect of World War II. Women who would ordinarily have had their children during the war years delayed their families, so that their children were born at a later time in their lives. If these two effects are taken into account, no real shifts in birth distribution can be found for recent years.

When we view birth distribution around the world, however, we find many real differences. In countries such as India,a sizable portion of the females are married in their very early teens and have their first child before they are 15 years of age. Other countries have a tradition of delayed fertility. The classical example is Ireland, where custom has delayed marriage and first children to the late 20's and early 30's.

Even if fertility were to remain constant, a change in birth distri- bution would result in a change in population growth. This avenue of population control has been advocated for countries with severe popula- tion problems, but it is probably doomed to failure since it often means the changing of ingrained social and religious patterns.

D, Sex Ratio of Offspring

More males are born than females. The sex ratio today is about 51.5% male births to 48.5% female. Why is this so?

In spite of the fact that according to Mendelian Laws there should be an equal chance of a male and female being conceived, there is good proof that this is not the case. Estimates made from the examination of spontaneous abortions (miscarriages) indicate that up to 170 males are conceived for every 100 females. While this estimate is probably too high, no estimates place the ratio near 50-50.

Reasons for this surplus production of males are as numerous as they are uncertain. This being the case, one can have a good deal of fun spec- ulating without fear of being contradicted. Some biologists have main- tained that males are conceived more often because the sperm carrying the Y chromosome is lighter than the sperm carrying the X chromosome and is, therefore, more likely to reach the egg cell.

Others have sought to explain this phenomenon in evolutionary terms. Some of this reasoning rests on the biological fact that the male fetus is less strong than his female counterpart. If in the past, the argument goes, living conditions were much less favorable, especially for the pregnant female, intrauterine conditions must also have been poor. Such a

State would naturally favor the production of females. Since a balanced »— production of males and females would seem to be biologically favorable, ae natural selection would favor those groups of pre-humans that had had a

tendency to produce a surplus of male conceptions, If this biological

trend were continued to the present day when prenatal conditions have

been vastly improved, a surplus of males would be born,

Many other interesting phenomena have been associated with sex-ratio differences. It has been noted that males occur in a higher percentage of first births and decline in majority with an increase in the mother's age. Scientists have used the argument about prenatal conditions to ex- plain this, saying that there is a more hostile intrauterine environment in women of older age, a condition that favors the female fetus. Also, increases in male births have been recorded during wartime, a phenomenon that is a good deal harder to explain,

A frequently cited cause of sex-ratio difference is race. It now appears that these differences are not real, but a result of under-regis- tration of female births by racial minorities,

Challenge your students to think of other reasons why more males might be born than females. It could be a very interesting way to review. both evolution and reproduction!

oe Mortality

Two disturbing facts have recently become evident concerning mortality in the United States, First, infant mortality in the U. S. is relatively high when compared with mortality in other advanced nations, Secondly, the U. S. is one of three nations in the entire world in which male life expectancy has actually fallen in the last 10 years,

At the present time the United States ranks 14th in infant mortality. This is a shocking figure, especially for a country that prides itself on being the most advanced technologically. The general infant mortality rate is approximately 28 deaths per 1000 live births. If you are a member of the lower class or an ethnic minority, things are even worse: infant mor- tality rises to 33 deaths per 1000 live births in these groups. Are there any biological factors that would explain this high rate? The answer is apparently no. Infant mortality for the upper-income brackets, where expensive prenatal care and counseling can be afforded, is only 17 per 1000 births. This would seem to indicate that the problem is not bio- logical, but social. :

Recently there have been attempts in the United States to come to grips with this problem. The March of Dimes is currently advertising through the “media to make women aware of the importance of prenatal medical care. But there is considerable doubt that the U. S. has the necessary personnel or facilities for all women to have the necessary prenatal care required to lower our infant mortality to a more acceptable level.

The problem of increased male mortality is more complex. After a steadily increasing rise in life expectancy throughout the 20th century, the United States has for the first time seen a drop in life expectancy among its male population, while females have continued to increase their life expectancy over the last 10 years. (See GRAPH 1 below.)

20

INCREASE MALE MORTALITY 1960-68

PERCENTAGE O

sa”, Oo STIS oF ToS sSTe s ERSBSSSRSBRR AGE GRAPH 1

What has caused this increase in male mortality? The United States has just completed a statistical survey to answer this question.* For

* "Leading Components of Upturn in Mortality for Men," DHEW Publication No.(HSM) 72-1008. (The Department of Health, Education and Welfare's document is available for 50¢ from the U.S. Government Printing Office.)

those males over 30 there has been a sizable increase in the incidence of

fatal lung cancer and other smoking-related diseases (such as emphysema) | over the past 10 years. Among males in their late teens and early twenties > the marked increases in mortality over the past 10 years have largely been

a result of automobile-related deaths, suicide and homicide. This pattern

has been substantially the same for all racial and economic groups.

The reasons for these increases in mortality are still open to con- troversy, but much more study is clearly warranted, since a continuation of this trend would result in a large surplus population of females in their reproductive years. Such a situation would have to lead to drastic changes in the operation of our society.

a O 50 a Lj O = 40 —— MALE LJ ——— FEMALE > in = 30 35 / S /' So 20-4 7 Se or \ / a \ / \ ve 2 lo \ 7 _ \ we . =a ra NS age O | OD o a ee eS ee GU WwW wm. 0 eee a . wan em 8 FS es AGE GRAPH 2

GRAPH 2 shows mortality/1000 versus age for both males and females. Two things to notice are (1) that females always have lower mortality, and (2) the especially high mortality for males in their 20's.

ry; Age Distribution

As mentioned earlier, all the other factors: fertility, birth distri- bution, sex ratio and mortality tend to influence the age structure of the population. In the United States today, the age structure is such that the median age is approximately 28 years. News media have often estimated a lower number when discussing the "youth revolution," but the fact remains that those over 30 are in the minority.

Countries with high birth rates and high mortality tend to have very young populations, while countries with low birth rates and low mortality have uniformly distributed or old-age-dominant distributions. This obser- vation has led to the concept of demographte transition, a process wherein falling mortality rates unaccompanied by falling birth rates produce a population explosion, with the birth rate declining only 100 years later. European countries underwent demographic transition during the 19th century. The surplus population produced during this process had a "safety valve" for expansion: namely, the North and South American continents.

Today, many countries are undergoing a similar demographic transition. This transition is producing even larger increases in population (from 2-37 per year), and there is no safety valve for expansion, The consequence is tremendous overcrowding and depletion of resources necessary for successful completion of this transition.

ITI. RUNNING USPOP

A. Explanation of Program Inputs

Due to the exceedingly large amount of information needed for the USPOP model, operational shortcuts were designed into the program. Instead of requiring the student to input over 80 numbers, the program stores (in DATA statements) the latest available statistics describing the U. S. population in 1970. The student should be encouraged to make maximum use of these statistics, as this will save him a great deal of time.

Should the student desire to use other variable values, the program allows him to try numerous values for all the variables. Variable values may also be changed during a RUN (by requesting a Number 4 Report).

What follows is an elaboration of the computer instructions given in the STUDENT MANUAL: | #1 DO YOU WANT REPORTS (1) EVERY 5-YEAR INTERVAL OR (2) SELECTED YEARS? Typing a "2" will enable the student to save a

great deal of time in the case of a long-term projection.

#2

#3

#4

#5

#6

#7

#8

YEAR AT START OF PROJECTION?

If the student is going to make extensive use of the data stored in the program, he should type "1970". If he is using data collected for another year, that year number should be typed.

DO YOU ASSUME STANDARD FERTILITY (1=YES, #=NO)?

This is a yes/no answer (l=yes, and $=no). If the student types "1", the computer will read the fertility from the 1970 data and skip to question #5.

If the answer was "no" (9), the computer will ask:

FERTILITY IN YEAR ?

The year number entered in #2 above should appear in the blank.

WILL FERTILITY (1) STAY CONSTANT OR (2) CHANGE SLOWLY TO A NEW LEVEL? The student enters the number that best represents the assumption he wishes to explore. If he selects "1", the computer will skip to question #8.

If the answer was "2":

WHAT FERTILITY WILL BE STABLE?

Student types fertility that he assumes will

eventually stay constant. (NOTE: at a later time in the RUN, this assumption may be changed.)

HOW MANY DECADES BEFORE FERTILITY REACHES STABILITY?

After the student answers Questions #6 and #7, the computer will have evaluated all factors related to total fertility.

DO YOU ASSUME STANDARD BIRTH DISTRIBUTION (1=YES, $=NO)?

This is also a yes/no answer. If the student types "1", 1970 data will be read from storage and the program will skip to question #10.

10

If the student typed "no" (@):

#9 PER CENT OF FERTILITY OCCURRING IN FEMALES AGES:

10-14?

15-19?

45-49? Student responds to these questions according to the situations he wishes to explore. The total for percentages must add to 100. After computer checks addition, program proceeds to question #10.

#10 DO YOU ASSUME STANDARD MORTALITY (1=YES, $=NO)?

Again this is a yes (1) no (@) question. If student types "1", 36 pieces of 1970 mortality data are read from the program. If he types "9", he may modify some or all of the male and female mortalities. If the student types "1", the program skips to question #13.

Otherwise:

ww | #11 CHANGE IN MORTALITY OCCURRING IN FEMALES (FROM AGE, TO AGE)?

Student sets lower and upper limits for range of age groups for which he wants to change mortality. For example, if he wants to change all mortalities, he should type "0,75". If the student does not wish to change the mortality rate for any female age group, he should type "9,9".

The computer then responds with:

GROUP CURRENT NEW VALUE

DEATH/1000

10-14 a ?

15-19 2s ?

75 & older 33763 ?

Following each question mark the student should enter _ the new value of mortality for that age group.

11

#12

#13

#14

#15

#16

CHANGE IN PER CENT MORTALITY OCCURRING IN MALES (FROM AGE, TO AGE)?

Exactly the same procedure as above, except that male mortality is now considered. Typing "¢,¢" will result in no change.

DO YOU ASSUME STANDARD POPULATIONS (1=YES, @=NO)?

Yes/no question (l=yes, @=no). If student types "1", the population is set equal to the 1970 population and computer skips to #16.

If student answers "no" (@): POPULATION CHANGE IN FEMALE GROUPS (FROM AGE, TO AGE)?

If student wishes to change the size of all popula-

tion cohorts, he would type "9,75". Should he want to make changes for only one or two age groups, leaving the rest at 1970 values, he might type "26,29", for example.

The computer would fespond with:

GROUP CURRENT NEW VALUE POPULATION MILLIONS 20-24 8.5 ? 6.9 ?

25-29 The student would then enter new values for the appropriate cohort populations in millions (decimal numbers allowed).

POPULATION CHANGE IN MALE GROUPS (FROM AGE, TO AGE)?

Same procedure as for #14,

REPORT: 1) SHORT 2) LONG 3) GRAPH 4) CHANGE ASSUMPTIONS 5) END?

Student can select any output format that he requires (for examples see Sample Runs included), obtain an option to change any variable values, or conclude

the RUN by typing the appropriate number.

The computer will then carry out all mathematics and issue a report

in the proper format, if a report is requested. After this, the

computer will return to question #16 for further instructions.

12

B. Additional Sample Runs (for more examples see USPOP TEACHER MANUAL )

In the Sample Run below, a student is carrying out a projection in

which he has altered birth-distribution assumptions. This facet of demo- graphy is studied in Investigation #2 in the STUDENT MANUAL.

DO YOU WANT REPORTS 1) EVERY 5 YEAR INTERVAL OR 2) SELECTED YEARS 71

YEAR AT START OF PROJECTION 71979

DO YOU ASSUME STANDARD FERTILITY C1=YES,%=N0) ?1

WILL FERTILITY ¢€1) STAY AT 2-45 OR (2) CHANGE SLOWLY

TO A NEW LEVEL ?1

DO YOU ASSUME STANDARD BIRTH DISTRIBUTION C1=YES»%4=N0) ?9

PCT. FERTILITY OCCURING IN FEMALES AGES: 19 - 14 739

45 AND OLDER ?6

DO YOU ASSUME STANDARD SEX RATIO C1=YESsG=NO) ?1 DO YOU ASSUME STANDARD MORTALITY (1=YESs@=NO) ?1

DO YOU ASSUME STANDARD POPULATION (1=YESs%=NO) ?1 REPORT!1)SHORT 2)LONG 3)GRAPH 4)CHANGE ASSUMPTIONS 5)END ?1 YFAR 1972 POP= 294.8 MILLION FERTILITY 2045 REPORT: ?1 YEAR 1975 POP= 218.9 MILLION FERTILITY 2045 REPORT: ?1 YEAR 1984 POP= 23369 MILLION FERTILITY 2245 REPORT: ?1

YEAR 1985 POP= 247-5 MILLION FERTILITY 20e45

13

REPORTs ?1

YEAR 1999 POQP= REPORTs ?1 YEAR 1995 POP= REPORT: 71 YEAR 2999 POP= REPORT: 25

ANOTHER PROJECTION

261 MILLION

27529

29204

C1=YES>

MILLION

MILLION

A=NO) 78

FERTILITY 2-45

FERTILITY 245

PERTILITY 2e45

In the following RUN, the student is investigating the effect of a slowly lowering fertility. Note the effect on the reports.

DO YOU WANT REPORTS 1) EVERY 5 YEAR INTERVAL | OR 2) SELECTED YEARS 72

BY TYPING "2" THE STUDENT MAY SKIP REPORTS.

YEAR AT START OF PROJECTION ?1975

DO YOU ASSUME STANDARD FERTILITY C1l*YESs@=N@) 79

FERTILITY IN 1975 22.96 ee WILL FERTILITY ¢1) STAY AT 2696 OR (2) CHANGE SLOWLY

TO A NEW LEVEL ?2

CHOICE "2" MAKES SLOW SHIFTS IN FERTILITY POSSIBLE WITHOUT INTER- RUPTING THE PROGRAM. FERTILITY WILL SLOWLY DROP TO 1 AND THEW REMAIN AT THAT LEVEL.

WHAT FERTILITY WILL BE STABLE 71 3 | HOW MANY DECADES UNTIL FERTILITY REACHES 1 ?3¢5

DO YOU ASSUME STANDARD BIRTH DISTRIBUTION Se 79 PCTe FERTILITY OCCURING IN FEMALES AGES: if ~ 24: 25

io =~ 49° 7238 29 - 24 7249 25 - 29 729 en Se SB K 3 gee oer

4% - 44 7245 45 AND OLDER ?6

DO YOU ASSUME STANDARD SEX RATIO C1=YESs%=NO) 22 PERCENT FEMALE BIRTHS 234

STUDENT HAS CHANGED THE BIRTH SEX RATIO SO 30% OF ALL LIVE BIRTHS ARE FEMALE AND 70%

ARE MALE,

15

DO YOU ASSUME STANDARD MORTALITY C1=¥ESs@=NO) 22 CHANGE IN MORTALITY OCCURING IN FEMALES GROUPS (FROM AGEs TO AGE) 2004

GROUP CURRENT NEW VALUE | DEATH/1009 A - 4 17.8 714 mane CHANGE IN MORTALITY OCCURING IN MALES es ALLOWE CHANGES IN STARTING GROUPS CFROM AGEs TO AGE) 20,4 YEAR POPULATION GROUP CURRENT NEW VALUE : DEATH/199@ Q-A4 2265 714

DO YOU ASSUME STANDARD POPULATION ¢(1=YES»@=NO0) 22

CHANGE IN FEMALE POPULATION ; GROUPS (FROM AGEs TO AGE) 70.2 | 9 wean 10 onan | CHANGE IN MALE POPULATION GROUPS CFROM AGEs TO AGE) ?155 34 ' t FE Bee POEULA TION MILEY ORS ae oe en 30 GLYEN, isaijos: 954 sa THEN STUDENT IS ASKED FOR 243 = 24 Be6 2403 NEW FIGURE, ALL VALUES 25 = 29 eR ny ARE IN MILLIONS. EXAMPLE: ca ae op =e 3.4 MEANS 3,400,000. | Pa REPORT:1)SHORT 2)LONG 3)GRAPH 4)CHANGE ASSUMPTIONS 5S) END ?2 YEAR 1975 POP= 192.4 MILLION FERTILITY 2.86 AGES FEMALES <-MILLIONS=> MALES PCTe TOTAL 8-4 824A 8.7 8e9 5 =- 9 907 19-1 14.3 19 - 14 1422 14-5 1968 1S = 19 924 8 9. 2A =< 24 Be5 403 6-6 2 34 <= 34 5-8 2e7 Ae 35 - 39 567 5.5 5.8 Py 49 = 44 601 508 601 45 ~- 49 62 5°09 603 54 = 54 507 5-3 507 55 = 59 5e2 4e7 Sel 63 =- 64 406 4 4e5 65 = 69 307 3 305 74 < 74 302 203 2eY 75 AND OVER 466 2e9 329

16

YEAR FOR NEXT

REPORT: 71

YEAR 1985

YEAR FOR NEXT

REPORT: ?1

YEAR

YEAR FOR NEXT

1995

REPORT: ?1

YEAR 24395

YEAR FOR NEXT

REPORT: ?2

IF REPORTS ARE TO BE GIVEN IN SELECTED YEARS:

AT THE END OF EACH REPORT THE COMPUTER ASKS FOR THE YEAR OF NEXT REPORT. ANY "FUTURE" YEAR MAY BE TYPED, BUT THE COMPUTER CAN ONLY RESPOND WITH AN INCREMENT OF 5 FROM THE

STARTING YEAR.

REPORT 71985 |

NOTE THE GRADUAL FALL IN FERTILITY

POP= 286-e9 MILLION FERTILITY 1.275714 REPORT ?1995 |

POP= 218e1 MILLION | FERTILITY 1445429 REPORT 72095

POP= 216¢9 MILLION FERTILITY 1215143 REPORT ?2815

POP= 247¢3 MILLION FERTILITY 1.

YEAR 2915

AGES FEMALES <-MILLIONS=> MALES PCTe TOTAL 6-4 1.7 309) Sat = y+ 9 2ei Ae 7 303

19 - 14 2.7 661 4e2

15 = 19 30e8 Bea 529

29 - 24 a. 15.4 703

25 = 29 523 11-4 Bel

39 = 34 524 11-6 8e2

35 = 39 562 11 7-8

AD 44 828 8-8 805

45 =< 49 929 | 907 925

55 - 54 19 s7 9.5

55 = 59 8e9 629 726

64 = 64 726 304 S03

65 + 69 5¢7 223 308

79 - 74 4e2 a e4 Qe 7

75 AND OVER 566 Aol 407

17

YEAR FOR NEXT REPORT ?2925 REPORT: ?1

YEAR 2925 POP= 191.3 MILLION FERTILITY 1. YEAR FOR NEXT REPORT 72935

REPORT: 71

YEAR 2935 POP= 168-1 MILLION FERTILITY le YEAR FOR NEXT REPORT 72045

REPORTS. 71

YEAR 2945 POP= 1489-8 MILLION FERTILITY 2. YEAR FOR NEXT REPORT 72455

REPORT: ?1

YEAR 2455 POP= 116 MILLION FERTILITY le

YEAR FOR NEXT REPORT 72349 SELECTED YEAR OPTION ALLOWS STUDENT TO EXAMINE LARGE TIME INTERVAL.

REPORT: ?2

YEAR 2399 POP= 31-4 MILLION FERTILITY te AGES FEMALES <-MILLIONS<-> MALES PCTe TOTAL A=- 4 Ae? Aeh 3 5S = 9 Aes Ne 7 3e7 io = {4 4e5 BeS AeA Pa 36 i 522 2a - 24 AeT Lel 509 25 = 29 B.S 1.2 6.5 30 =- 34 Aed 1.3 72 35: + 39 Ae9 1.3 7:04 49 - 44 1 cores 725 45 = 49 1 1.3 75 59 ~ 54 ! 1e3 <5 55 < 59 1 1.2 7e3 6% - 64 1 lel. 609 65 = 69 Ae9 AeY Hel 70 = 74 Se 8 Ae Tl S 75 AND OVER 1.5 i %e2

YEAR FOR NEXT REPORT 23000 ~

TO END PROJECTION, IT IS STILL NECESSARY TO SET A DATE FOR NEXT REPORT.

REPORTS 4:

ANOTHER PROJECTION C1SYES» 9=NO) 20-

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TV. The USPOP MODEL

A. About the Model

USPOP can be used to model any human population. In the course of developing the program, we made certain simplifying assumptions in order to reduce the size of the program and make it usable on smaller computers. As it stands, USPOP makes use of over 80 variables to delineate population behavior characteristics; if the model were more sophisticated, even more variables would be required to describe the population's characteristics.

The assumptions under which USPOP operates will not affect the model's performance to any noticeable extent if the population being modeled is sufficiently large; for a smaller population (under 500,000), however, some deviation may occur.

Clearly, in a model of a large population, each person cannot be depicted individually and assigned a unique set of variables for descriptive purposes. The individuals within a population are always placed into similar groups called cohorts. Closeness of age is one of the prime characteristics of a cohort; in addition, cohorts are often defined by sex. Very simple population models consider the population to be composed of either one or two cohorts. (This was the case in the HUNTINGTON TWO simulation POP.) The USPOP model considers the population to be composed of 32 cohorts, 16 of either sex. Each cohort is composed of those born in a contiguous 5-year period; therefore, the cohorts cover ages 0 to 4, 5 to 9, 10 to 14.....and 7-0: 75, All members of a particular cohort share the general charac- teristics of the group, as specified in its set of variable values. Natur- ally this procedure simplifies the calculations involved in making the projection.

The calculations can be made still easier if we are content to look at the population only at 5-year intervals. By doing so, we can view each cohort as "graduating" together into the next age category. Of course, we do incur some error in doing this, but if the population is large enough, the error is usually so small that a 5-year calculating period is not objectionable. (Should you attempt to model a small popu- lation, however, you might detect deviations.)

Other Applications of the USPOP Model

Although this program was done with U. S. data, it is a general human population model and may be applied to any population -- provided the fol- lowing statistical information about the population can either be gathered or estimated:

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1) Fertility - average number of live births per woman over her reproductive lifetime. For those women still in the reproductive ages, estimates must be made for the number of children they are likely to have. Note that non- reproductive women must also be considered in estimating the fertility.

2) Birth distribution - per cent of total fertility expressed by females of each age category. Estimates of this may be obtained from interviews or from relevant hospital records.

3) Sex ratio of offspring - per cent of live births: female and/or male.

4) Mortality rates - deaths per 1000 individuals in a single cohort over a 5-year period. These will be difficult to obtain. You may elect to use the same figures published for the country as a whole,

5) Populations of each cohort at beginning year. These can be obtained from any census taken for the area which you are modeling.*

Specific Suggestions

* Have your students attempt to obtain the above information for your community; then have them use USPOP to project the population of their community into the future. Discuss —_ what these changes could mean to the community and to them personally. (USPOP assumes a net immigration of 400,000 individuals per year. To eliminate this, see Part F of

Section IV.)

* Run comparative population projections for several coun- tries. Data should be available through the World Health Organization of the United Nations. Have your students write both to WHO and embassies of countries that they are interested in to ask for the above information.

B. USPOP Model Formulas

1) Total population:

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Pp. = = .(M.. +-F,) ° be i

Where M, equals the ith cohort of males and F, the ith cohort

of females. (Each cohort represents a group Born within a 5-year period.) P. equals the total population at time t. This assumes immigration is constant at 400,000 per year. M._-. and F_, include all those age 75 and over. = ae

ere = *See references for sources in your area.

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2) Births in the population:

10 : B= £5, x F.) icy i

where f equals the total fertility, and D; the per cent @ fertility expressed by the ith female cohort. The limit-

ing values of i assume that all births occur to females

between the ages of 10-49. Also no direct male influence 7 on births is assumed, as no M factor is used.

a) Male births: M = mB O where m equals per cent of all male births. b) Female births:

Fo = 5,

3) Fertility determination: f= (f, +f.) /2

Fertility over the 5-year calculating period is assumed to be equal to the mean average of fertility at the beginning of the period (f,) and fertility at the end of the period (f,).

e 4) Mortality: