DOC-20240711-WA0008.pptx for nursing students

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1. DEMOGRAPHY BY J. SAGAWA

2. LEARNING OBJECTIVES By the end of this session, learners should be able to: Define what demography is Outline specific variables used in demography Identify sources of population/demographic data Demonstrate an understanding of demographic measures Explain the measures of population change

3. DEFINITION AND DESRIPTION OF DEMOGRAPHY Demography is the description, analysis and understanding of human population phenomenon It covers aspects of social, economic, historical, political, biological, genetic and geographic characteristics of human population Demography is also simply defined as science of population Demography seeks a mathematical and statistical description of human population- e.g. how many are females, how many are elderly, how many are educated It is also broadly known as the study of human population

4. Demography has an implication in social, economic, historical, political aspect of a society For example, if an area has a lot of school aged children, then in planning you can consider building a school in that area Thus, demography may help in planning

5. SPECIFIC VARIABLES IN DEMOGRAPHY Specific demographic variables may include: Place of birth Education level Marital status Occupation Income Place of residence Age Sex Age composition Sex composition e.t.c.

6. SOURCES OF DEMOGRAPHIC/POPULATION DATA National sources of demographic data International sources of demographic data There are a number of national sources of population data and they include the following Population census Sample surveys Vital Registration S ystem Population registers Non-traditional sources-hospital records, school records e.t.c

7. NATIONAL SOURCES OF POPULATION DATA National census This is the total process of collecting, compiling, and publishing demographic , economic, and social data pertaining at a specified time or times to all persons in a country or delineated territory Census has a time factor, thus it is performed at a specific time A census has the properties of individual enumeration, universality, and simultaneity (same time)

8. UGANDA’S PAST CENSUS POPULATION (IN MILLIONS) YEAR POPULATION 1948 5.0 1959 6.5 1969 9.5 1980 12.6 1991 16.7 2002 24.4

9. MALAWI’S PAST CENSUS POPULATION (IN MILLIONS) Students activity Look for the population censuses for Malawi for the past 5 decades

10. Merits of Census True representation of the whole population Complete enumeration of all persons Absence of sampling errors Few questions are asked so its not much tiresome Demerits of census Extremely expensive in nature In most developing countries generally are decennial (done every 10 years) in contrast to more developed countries where quinquennial (at interval of 5 years) exercises are common

11. Long inter- censal periods work against availability of current data required for planning Only a limited number of questions can be asked therefore no generation of rich/detailed data Time consuming as it covers the whole population (data collection and analysis) Presence of non-sampling errors (some people may not manage to respond bringing some errors in the quality of data)

12. Demographic surveys These seek to collect information only from a fraction/sample of the population The data collected are used to provide estimates of size fertility, mortality, migration, growth rates, and other characteristics Many developing countries have conducted Demographic Health Surveys for the last 20 to 30 years Other surveys have been conducted such as: AIS (AIDS I ndicator Survey) Malaria surveys

13. Merits of surveys Relatively lower costs (in comparison with a census) Sampling allows an in-depth study of objects in the population Increases accuracy of results (owing to control over a small number of subjects) Convenient when population is scattered over a wide geographical area Demerits of surveys Sampling errors Interview fatigue It needs experts to analyze and interpret the data

14. 3. Vital Registration System (VRS) This is an institution arrangement of continuous registration of births, deaths, marriages, divorces, annulments/dissolutions These institutions may include hospitals, district councils, City council, NGOs These do conduct regular/continuous demographic events happening in their institution For example, if a baby is born at the hospital the details are recorded in birth register for that hospital, and when death occurs, the details including the cause, age, sex, and other characteristics are recorded in the death register

15. It is well established/ entranched in More Developed Countries (MDC) In contrasts, the arrangement is either defective or non-existence in most Low Developed Countries (LDC) In such countries (LDC), vital registration system data may not provide reliable estimates of demographical levels and trends Merits of VRS It gives accurate information/ its updated there and then when the event happen It helps the government in planning Assist in predicting population change

16. Demerits of VRS I t requires motivation and supervision Time consuming Some events may be missed-those not reported hence can’t give true reflection 4. Population Registers This is a regularly updated list of people resident in a country It includes particulars of individuals such as date of birth, sex, marital status, religion, occupation, nationality, education level etc It is regularly updated This source of data is well developed/entrenched in Scandinavian countries (like F inland, Denmark, Sweeden )

17. SELECTED INTERNATIONAL SOURCES OF DEMOGRAPHIC DATA United Nations Demographic Yearbook It was established in 1948 It contains internationally comparable and comprehensive annual statistics on population fertility, mortality, urbanization among others Its handy for governments, private institutions, and researchers 2. Demographic H andbook for Africa This was established/published by Economic Commission for Africa (ECA) It contains data on African countries 3. World Health Organization Print and Electronic Resources Concerned with the health issues of the world population

18. 4 . UNDP Publications This include Human Development Reports (HDR) 5. World Bank Publications 6. Assorted Print and Electronic Journals

19. DEMOGRAPHIC MEASURES These are tools for demographic analysis Basic measures include: Count Ratio Proportion Rate

20. COUNT This is an absolute number of a population or any other demographic event occurring in a specific area in a specified period Counts are raw numbers that are the basis of all other demographic computations Example 136,000 deaths among persons aged 15-49 years in Malawi in 2008 Death=demographic event Malawi=specified area 2008=specified period 136,000 is a raw number, it does not tell us much/they don’t tell the whole story-whether this is high or low

21. Counts are good, as they give us a starting point However, they do not control differences in population sizes In formal demography, ratios, proportions and rates are superior than counts as they enable comparison by eliminating differences due to population sizes

22. RATIOS This is the relationship of one population subgroup to another subgroup (of the population) or to the total population It compares relationship between two different variables (i.e. mothers to babies) Example of ratios Sex ratio at birth Doctor-population ratio Teacher-pupil ratio Computer-student ratio These are however obtained from counts

23. PROPORTION This is a special type of ratio in which the numerator is included in the denominator It takes the format Proportion= It ranges from 0.0-1.0 thus, it ranges from 0 to 1 It may also be expressed as a fraction or percentage For example 2/3 of the population are males or 60% of the population are females  

24. Examples of proportion A female proportion in a class Elderly proportion Urban proportion For Uganda for example urban proportion is 13% and Rural proportion is 87%

25. RATE This is the most common demographic measure It is the frequency of demographic events in a population during a specified period divided by the “population at risk” (population currently exposed to the event) Rates compare similar things e.g. women against women and they factor in a constant Examples of Rates Birth rates Death rates Marriage rates Migration rates Divorce rates Death rates

26. Example 137,000 deaths among persons aged 15-49 years (in Malawi) in 2012 14,000,000 population aged 15-49 years (in Malawi) in 2012 Calculate the death rate for Malawi Death rate= x1000 Dearth rate= x1000 Death rate = 9.8 T o the nearest whole number= 10 (people cannot be expressed in decimals) Interpretation: For every 1000 people aged 15-49 years, about 10 people died in 2012  

27. Exercise Calculate and interpret the death rate for china given the following information: 2,249,600 deaths among persons aged 15-49 years in 2006 913,256,000 total population aged 15-49 years in 2006

28. This shows that rates are superior to other measures since they tell the real story Thus, by looking at the given counts (raw numbers) between those two countries, one would imagine that there were many deaths in china than in Malawi, which is not the case in the given scenario

29. CONSTANT This is non-changing number by which rates, ratio or proportions can be multiplied to express these measures in a more understandable form Common constants are: 100, 1000, 100,000 In the above scenario for Malawi, if constant was not applied the rate would be like: = 0.00979 This could not give a clear meaning of the event The constant also helps to eliminate the errors due to different population sizes Note : Where the incidences are so low, we need to use a big constant to avoid decimals  

30. COHORT MEASURE A cohort is a group of persons having a common or shared characteristics For example: Birth cohort Class cohort Marriage cohort These are followed for a long time-to have meaningful results A cohort measure is a statistic that measure events occurring to a cohort (and the procedure is cohort analysis)

31. PERIOD MEASURE This is the statistics that measure events occurring to all or part of a population during one period of time (usually in a year) This measure takes a snapshot of a population at one point in time This is a common measure adopted in many demographic analyses

32. CRUDE RATES AND SPECIFIC RATES Crude rates and specific rates are two types of rates usually used in demographic analysis Crude rates relate number of events in a period to population size in the same period Examples of Crude Rates Crude birth rate Crude marriage rate Crude re-marriage rate Crude divorce rate Crude death rate

33. The problem with crude rates is that they don’t control all population of interest and are not specific for age or any specific variations like age, sex This makes crude rate of little significance However, it gives a good quick picture of mortality situation of general population e.g. 20% death rate Calculating Crude rates: Crude Death Rate (CDR): CDR= K Where D= Number of deaths in a population P=mid-year population K=Constant (Usually 1000)  

34. B. Crude Birth Rate (CBR) CBR= K Where: B=Number of birth in a population P=Mid-year population K=Constant (usually 1000) Student activity: Work out for a CBR in a population where total number of birth in 2009 was 20,000 and mid-year population was 13,000,000.  

35. Demerits of Crude Rates Crude rates mask important details They lack refinement and thus they are of limited value For example, Crude birth rates offer no idea of variation in birth by age and sex Obviously, children, men and oldest females are not part of at risk of conception and birth but are included in the denominator

36. SPECIFIC RATES These are more refined and less general They target particular population Notable Examples of Specific Rates Age-specific death rates Age-specific birth rates Sex-specific death rates Cause-specific death rates

37. AGE SPECIFIC BIRTH RATE Interval (I) Live Birth Number of women Age-specific Birth Rate 15-19 1500 20,000 1500/20,000*1000=75/1000 women 20-24 1600 21,000 25-29 1800 50,000 30-34 2500 26,000 35-39 1300 29,000 40-44 1100 30,000 45-49 310 30,000

38. AGE-SPECIFIC DEATH RATE INTERVAL DEATHS POPULATION AGE-SPECIFIC DEATH RATE <1 (infant mortality) 500 20,000 500/20,000*1000= 25 deaths/1000 under ones 1-4 300 21,000 5-9 280 50,000 10-14 201 26,000 15-19 150 29,000 85+ (end point) 100 30,000

39. Note: in developing countries the death rate follows/looks like the U-shape while in developed countries it follows J-shape Thus, there is high infant mortality in developing countries due to birth injuries, congenital abnormalities, low immunity, and at middle age group there are less deaths due to increased immunity and resilience to diseases, and then there is increased deaths due to old age in later ages In developed countries, there is low infant death rate due to increases care and high technology at birth , and higher death rate in elderly due to high incidences of non-communicable diseases like cancer ,HBP, diabetes among others

40. Cause-Specific Death Rate (CSDR) CSDR= *C Note: We use mid-year population because we assume that the people available at mid-year are likely to have been in that population at the beginning of the year and are likely to be in the population by the end of the year  

41. CENTRAL RATES/MID-YEAR POPULATION This is the population as at 30 th June/1 st July of a year and is used to compute central rates The population may slightly differ from the mean population where seasonal fluctuations exists However, the mid-year is usually taken as arithmetic mean of the population for the two 1 st January dates that bound a year in question

42. ESTIMATION OF MID-YEAR POPULATION This can be done by the method of arithmetic linear interpolation Thus, estimating a value that lies between two points/relationship between two points This method(linear interpolation) takes the following formula: Ā= ( + ) Where: Ā=Mid year population i =Length of time between the earlier known date n=length of time interval =Population size at earlier time “t” =Population size at the later time “t+n”  

43. EXAMPLE The population at beginning of interval (1 st January, 2011) is 10,512,000 The population at 1 st January,2012 is 13,124,000 What was the estimate of the mid-year population as of June, 2011? i =6 months (June 2011) n=12 months (January, 2012) Ā= ( 10,512,000+13,124,000) Ā=11,818,000 Thus, 11,818,000 is the population at 30 th June/1 st July, 2011(mid-year population)  

44. MEASURES OF POPULATION CHANGE There are two approaches used Rate of Natural increase (RNI) Rate of Population Growth (Growth rate)/GR Rate of Natural Increase This focuses on the difference between Crude Birth Rate (CBR) and Crude Death Rate and is often expresses as a percentage Example Let CBR=47/1000 and CDR=22/1000 RNI= *100 RNI= *100 RNI=2.5%  

45. This means that the population is growing at 2.5% due to natural causes of birth and death However, this is not giving a complete picture because there is migration component which also affect population growth Rate of Population Growth (GR) This takes into consideration all the three components of population dynamics; that’s Birth, Deaths and Migration It is a rate of natural increase adjusted for net-migration It may be computed for one year period or longer interval/period

46. Formula for GR r=( )-1 Where r=population Growth Rate Example: Population for January, 2008=10,554,000 Population for January, 2009=10,900,000 r=( )-1 r=0.0327 Since GR is expressed in percentage, then: r=0.0327*100 r=3.3%  

47. THE END QUESTIONS AND COMMENTS