04. Demographic statistics chapter 4.pptx

Demographic statistics about population

1. Demographic Statistics CHAPTER FOUR

2. DEFINITION Demography : is composed of two Greek words, namely, ‘ d emos ’ meaning people and ‘ g raphien ’ meaning to describe Therefore, demography means description of people or the scientific study of human population Demography is the scientific study of human population and its dynamics

3. DEFINITION… Demography is a science that studies human population with respect to size , distribution , composition , social mobility and its variation with respect to all the above features and the causes of such variation and the effect of all these on health, social, ethical, and economic conditions The focuses of demography are 1. Size 2 . Composition (structure) 3 . Distribution and 4 . Changes

4. DEFINITION… The focuses of demography are 1. Size 2 . Composition (structure) 3 . Distribution and 4 . Changes

5. DEFINITION… Size : is the number of persons in the population at a given time Example: The size of Ethiopian population in 2002 is about 65 million Distribution : is the arrangement of the population in the territory of the nation in geographical, residential area, climatic zone, etc Example: Distribution of Ethiopian population by Zone

6. DEFINITION… Composition (Structure): is the distribution of a population into its various groupings mainly by age and sex Change : refers to the increase or decline of the total population or its components The components of change are birth, death, and migration

7. Sources of Demographic Data Demographic data are important in providing factual basis for decisions on matters of public policy and action concerning social and economic affairs These data indicate present and future requirements of the population such as health, education and employment

8. Sources of Demographic Data… Demographic information can be acquired through two main ways: 1.Enumeration Method Census Survey 2.Registration Method Vital registration system (VRS)

9. 1. Census a nation-wide counting of population it is obtained by a direct canvass of each person or household, which is a large and complicated undertaking is a periodic total count or enumeration of population the first census in Ethiopia was undergone in 1984 E.C

10. Census… There are two main different schemes for enumerating peoples in a census De jure : enumeration or count is done according to the usual or legal residence ( permanent residence ) A de jure count of the members of a house hold excludes temporary residents and visitors, but includes permanent residents who are temporarily away

11. Census… Advantage De jure : yields information relatively unaffected by the seasonal fluctuations Disadvantages Some persons may be omitted from the count while some others may be counted twice In some situations, it is difficult to be sure just which is a person’s usual or legal residence Information collected regarding persons away from home is often incomplete or incorrect

12. Census… De facto : enumeration is done according to the actual place of residence on the day of the census A de facto count includes temporary residents and visitors , but excludes permanent residents who happen to be away on the day of the census

13. Census… Advantage De facto: offers less chance of double counting and omission Disadvantages Population figures may be inflated or deflated by tourists, traveling salesmen, and other transients In areas with high migration, the registration of vital events (vital statistics) is subject (liable) to distortion

14. CHARACTERISTICS OF A CENSUS 1. Individual enumeration 2. Universality within defined territory (It should refer to the people inhabiting a well defined territory) 3. Simultaneity (enumeration with respect to a well defined point in time) 4. Defined periodicity (It should be taken at regular intervals usually ten years)

15. CENSUS OPERATION The entire census operation has 3 stages: 1) Pre- enumeration :- planning and preparatory work 2) Enumeration :- field work (data collection) 3) Post- enumeration :- editing, coding, compilation, tabulation, analysis, and publication of results

16. Cont’d Data that are collected through census are:- Sex Educational x-tics Age Economic x-tics Marital status Place of birth Language Mortality Fertility Citizenship Living conditions( house ownership , types of housing and the like…. Religion

17. Uses of a census 1. Gives complete and valid picture of the population composition and characteristics 2. Serves as a sampling frame 3. Provides with vital statistics of the population in terms of fertility and mortality 4. Census data are utilized in a number of ways for planning the welfare of the people

18. Limitations of a Census Size limits content and quality control efforts Cost limits frequency Delay between field work and results Sometimes politicized Limited information obtainable Vast personnel requirement

19. 2. SURVEY it is a one time data collection from the representative samples method of study conducted on a representative samples to obtain more comprehensive information the data is use for monitoring the health status of the population they are made at a given moment, in specific territory without periodicity to obtain information from part of the population which is considered to be representative

20. SURVEY Population Sample . Information

21. VITAL REGISTRATION SYSTEM is a system by which all births , deaths , etc. occurring nationwide are registered, reported to a control body and compiled centrally a certificate is issued for every death and birth because the cause of death is registered on the certificate it is possible to calculate cause specific death rates not well developed in Ethiopia and hence cannot serve as a reliable means of getting information

22. The main characteristics of vital statistics are:- Compulsory by law: -should be enforced by law Compiled centrally:- so it can serve as a source of information Comprehensive: -all deaths and births are registered Continuous: -is an ongoing process

23. POPULATION COMPOSITION AGE-SEX COMPOSITION Age and sex are the most important/ basic characteristics of a population It refers to the number or proportion of males and females on each age group Every population has a different age and sex composition

24. POPULATION PYRAMID Population pyramid is a graphical display of age and sex composition at a given time It shows numbers or proportions of males and females in each age group It is the most widely used of all graphic devices in population studies It presents the population of an area or country in terms of its composition by age and sex at a point in time

25. POPULATION PYRAMID… Normally forms the shape of a pyramid C onsists of two back-to-back bar graphs, with the population plotted on the X-axis and age on the Y-axis One showing the number of males and one showing females in a particular population in five-year age groups Males are shown on the left and females on the right

26. POPULATION PYRAMID… By convention , males are shown on the left of the pyramid, females on the right, young person’s at the bottom, and the elderly at the top The pyramid consists of a series of bars, each drawn proportionately to represent the percentage contribution of each age-sex group (often in five-year groupings) to the total population; that is, the total area of the bars represents 100% of the population

27. Population Pyramid…

28. Population Pyramid… The shape of the pyramid is the direct or indirect effect of the influence of the past events such as births, deaths or migration

29. STAGES IN DEMOGRAPHIC TRANSITION Demographic transition refers to the change that populations undergo from high rates of births and deaths to low rates of births and deaths The theory of demographic transition attempts to explain the changes in mortality and fertility in three different stages therefore we distinguish among three types of pyramid

30. 1. PRE-TRANSITIONAL Characterized by High Mortality and High Fertility, with low (moderate) population growth (young population) It can be shown by Triangular , broad based pattern reflecting the high birth rates This type of population is found in primitive societies and is sometimes known as Expansive Type I/Stage I . (Expansive Pyramid )

31. 2. Transitional Characterized by high birth rate and reduced death rates, with high (rapid) growth rate (young population) The drop in the death rate is usually brought about by improved medical care following socio economic development The shape of the population pyramid is triangular characterizing a developing society Sometimes known as Expansive Type II/ STAGE II

32. 3. POST-TRANSITIONAL Characterized by low birth and death rates with stable, moderate growth rate Narrow based pyramid and steeper sides This is typical of advanced or developed countries and is sometimes known as Stationary Type III / STAGE III . (STATIONARY PYRAMID) NOTE: When constructing a pyramid using a percentage, take the percentage from the group total

33. MEASURES OF VITAL STATISTICS 1. Rate Usually implies the probability of the occurrence of some event It is a special type of proportion with time elements , i.e. in which occurrences are quantified over a period of time They measure the likelihood of occurrences of phenomena within the given population Time , place and population are the crucial elements of the rate

34. Rate… A proportion with a time element Rates Could be Crude or Specific Crude - calculated for the entire population - affected by the structure of the population Specific -calculated for a particular category

35. 2. Ratio The quotient of two numbers Numerator NOT included in the denominator No relationship necessary between numerator and denominator May be expressed as a/b or a:b

36. 3. Proportion The quotient of two numbers Numerator is a sub-group of the population in the denominator Numerator is always INCLUDED in the denominator Proportion ranges between 0 and 1 Percentage = proportion x 100

37. Summary

38. 1. Measures of Fertility Fertility is the reproductive performance of an individual, a couple, a group or a population It is meant the actual bearing of children It leads to increase of population Fecundity – which refers to the physiological capability of a woman to reproduce A woman’s reproductive period is roughly 15 – 49 years of age

39. The most important measures of fertility include 1.1. Crude Birth Rate (CBR) The crude birth rate indicates the number of live births (children born alive) per 1000 mid – year population in a given year In the world CBR varies widely from population to population It is high for population of the developing countries and low for those of the developed ones

40. Crude Birth Rate (CBR)… CBR= Number of live births/year X 1000 Total Mid-year population

41. 1.2 . General Fertility Rate (GFR) is the number of live births per 1000 females aged 15-49 years (fertile age group) in a given year it more sensitive measure of fertility than the CBR, since it refers to the age and sex group capable of giving birth (females 15-49 years of age) the major limitation of GFR is that not all women in the denominator are exposed to the risk of child birth

42. General Fertility Rate (GFR… GFR= Number of births/year x 1000 Number of women ages 15 to 49

43. 1.3 Age specific fertility rates (ASFR) the number of children born alive to females in a specific age group per 1000 females in that specific age group Example (15-19), (20-24),….. (45-49) years of age ASRF= Number of births to women age A X 1000 Number of women age A

44. ASFR…. For example, ASFR for women 20 – 24 years of age is expressed as : ASRF= Number of births to women (20-24yrs) X 1000 Number of women (20-24yrs) For instance if there were 4,000,000 women (females) in the age group 20-24 years and if the there were 200,000 live births to women in the same age group, the Age specific fertility rate for these women (20-24 years of age) will be; ASFR (20-24) years of age = 200,000/4,000,000 X 1000 = 50 That is, there are 50 live births for every 1000 women 20-24 years of age

45. 1.4. Total Fertility Rate (TFR) is number of children a woman will have if she lives through all the reproductive ages and follows the age specific fertility rates of a given time period (usually one year) it is best single measures to compare fertility across populations

46. 1.5. Gross Reproduction Rate (GRR) is the average number of daughters that would be born to a woman throughout her lifetime or child bearing age (15-49 years), if she were to pass through all her child bearing age NOTE GRR is exactly like TFR, except that it counts only daughters and literally measures “reproduction” A women reproducing herself in the next generation by having a daughter

47. Gross Reproduction Rate (GRR).. GRR = TFR X Female births Male + Female births Example: - The sex ratio at birth of Ethiopia (2001) = 100.6 ( i.e 100.6 males for every 100 females) - and the TFR (2001) = 5.9 (5.9 children per women) GRR = TFR X proportion of female births GRR = 5.9 X 100 = 2.94 200.6 = 2.9 daughters /woman

48. 1.6. Child – Woman Ratio (CWR) Child-Women ratio : Number of children under age 5 per 1000 women of childbearing age in a given year Number of children (1-4)yrs X 1000 Number of women ages 15-49 E.g If the number of children under 5 years of age in an area is 2,000,000 and the number of women 15 – 49 years of age is 8,000,000

49. Child – Woman Ratio (CWR)… The CWR = 2,000,000 X 1000 = 250 8,000,000 1000 That is 250 children 1 – 4 years of age (under five) per 1000 women of the reproductive age

50. 2. Measures of Mortality Mortality refers to deaths that occur within a population (reduction of population) The incidence of death can reveal much about the living standard, the health status of a population and the availability of health services Mortality (Death) rates have three essential elements: A population group exposed to the risk of death (denominator) The number of deaths occurring in that population group (numerator) A time period

51. 2.1. Crude Death (Mortality) Rate (CDR) is the number of deaths per 1000 population in a given year CDR = Total number of deaths in a year X 1000 Mid-year population it is not a sensitive measure (indicator) of health status of a population it is affected by particularly the age structure of the population

52. 2.2.Age specific Death (Mortality) Rates it is calculated in order to compare mortality at different age groups E.g. for infants (< one year of age), children 1-4 yeas of age, children under five years, etc ASMR= Number of deaths in a specific age group X 1000 Mid-year population of the same age group

53. 1. Infant Mortality Rate (IMR) is the number of deaths of infants under one year of age (0-11 months of age) per 1000 live births in a given year infants are at highest risk of death than any other age group IMR = Number of death of children < 1 year of age in a year X 1000 Total live births during that year

54. Infant Mortality Rate The infant mortality rate is considered to be a sensitive indicator of the health status of a community, it Reflects the socio-economic condition of the population; i.e. the level of education environmental sanitation adequate and safe water supply communicable diseases provision of health services etc

55. 2. Child Mortality Rate (CMR) It is the number of deaths of children 1-4 years of age per 1000 children 1-4 years of age It is a sensitive indicators of the health status of a community CMR = Number of deaths of children 1-4 year of age in a year X 1000 Total number of children 1-4 years of age

56. 3. Under Five Mortality Rate (<5MR ) It is the number of deaths of children under five years of age in a year (0-5 years of age) per 1000 children under five years of age (0-5 year) It is also a very good indicator of the health states of a community <5MR = Number of deaths of children <5 yrs in a year X 1000 Total number of children < 5 years of age According to Health and Health Related Indicators (MOH), the under five mortality Rate of Ethiopia is estimated to be: - 140/1000 live births, currently ???? - 161/1000 live births, (1994)

57. 4. Neonatal Mortality Rate (NNMR) is the death of infants under one month (<4 weeks) Per 1000 live births NNMR = Number of deaths of infants < 1 mouth in a year X 1000 Total number of live births in the same year It is an indicator of the level of prenatal and obstetric components of maternal and child health care (MCH)

58. 5. Post-Neonatal Mortality Rate (PNNMR) is deaths of infants one month (four weeks) of age up to one year (1 – 11 months age of) per 1000 live births PNNMR = Number of deaths of infants 1 month to 1 year of age in a year X 1000 Total Number of live births during the same year The post-neonatal mortality rate reflects deaths due to factors related to; Environmental sanitation Infections (communicable diseases) Nutritional problems Child care etc

59. 6. Maternal Mortality Ratio (MMR) is the number of maternal deaths related to pregnancy, child birth and post natal ( peurperium ) complications per 1000 live births (usually per 100,000 L.B) MMR = Number of deaths of women related to pregnancy, child birth and peurperium in a year X 100,000 Total number of live births in the same year

60. MMR… . It is a sensitive indicator of health status of a population It reflects the socio- economic status of a community The Maternal Mortality Ratio of Ethiopia is estimated to be more than 676 deaths per 100,000 live births annually This is among the highest in the world!

61. 7. Maternal mortality rate(MMR) MMR = No. of maternal deaths in a specified period *1000 No. of women of reproductive age

62. 8. Sex Specific Death Rates (SSDR) the number of deaths among a specific sex group (males or females) per 1000 population of the same sex group SSDR= Number of deaths among males X 100 Total number of males Sex specific mortality rate is used to determine which sex group is at higher risk of death than the other

63. How can we describe the Impact of population composition on Health, Social and Economy? 1. Age dependency ratio : Ratio of persons in the dependent ages ( under 15 and over 65) to those in the economically productive ages P(0-14 ) + (P65+) X 100 p15-64

64. HEALTH SERVICES STATISTICS are very useful to improve the health situation of the population of a given country For example, the following questions could not be answered correctly unless the health statistics of a given area is consolidated and given due emphasis What is the leading cause of death in this area? Is it malaria, tuberculosis, etc? At what age is the mortality highest, and from what disease?

65. HEALTH SERVICES STATISTICS… Are certain diseases affecting specified groups of the population more than others?) In comparison with similar areas, is this area healthier or not? Are the health institutions in the area able to cope with the disease problem? Is there any season at which various diseases have a tendency to break out? If so, can these be distinguished? What are the factors involved in the incidence of certain diseases, like malaria, tuberculosis, etc.?

66. USES OF HEALTH STATISTICS Describe the level of community health Diagnose community ills Discover solutions to health problems and find clues for administrative action Determine priorities for health programme Develop procedures, definitions, techniques such as recording systems, sampling schemes, etc. Promote health legislation

67. USES OF HEALTH STATISTICS… Create administrative standards of health activities Determine the met and unmet health needs Disseminate information on the health situation and health programmes Determine success or failure of specific health programmes or undertake overall evaluation of public health work Demand public support for health work

68. Major limitations of morbidity and mortality data from health institutions in Ethiopia include the following Lack of completeness : Health services at present (in 2000) cover only 47% of the population……87%??? 2007 E.C Lack of representativeness : Illnesses and deaths recorded by health institutions do not constitute a representative sample of all illnesses & deaths occurring in the community Lack of denominator : the underlying population served by a health institution is difficult to define

69. Major limitations of morbidity…. Lack of uniformity in quality : no laboratory facilities in health stations, such facilities are available in hospitals Lack of compliance with reporting : reports may be incomplete, not sent on time or not sent at all

70. Health service utilization rates (Hospital statistics) Admission rate (AR): the number of (hospital) admissions per 1000 of the population per year “ Admission” is the acceptance of an in-patient by a hospital Discharges and deaths:- the annual number of discharges includes the number of patients who have left the hospital (cured, improved, etc.), the number who have transferred to another health institution, and the number who have died

71. Health service utilization rates… Admission rate = Number of Admissions in the year ×1000 Total Population of the Catchment area

72. Health service utilization rates… 2. Average Length of Stay (ALS) indicates the average period in hospital (in days) per patient admitted ALS = The Annual Number of Hospitalized Patient Days Number of Discharges and Deaths

73. Health service utilization rates… 3. Bed-occupancy rate (BOR) expresses the average percentage occupancy of hospital beds BOR = The Annual Number of Hospitalized Patient Days × 1 Total Number of Beds 365

74. Health service utilization rates… 4. Turnover interval (TI) the turnover interval expresses the average period, in days, that a bed remains empty the average time elapsing between the discharge of one patient and the admission of the next TI = (365 × Number of Beds) - Number of Hospitalized Patient Days Number of Discharges and Deaths

75. Health service utilization rates… The turnover interval is zero when the bed-occupancy rate is 100% A very short or negative turnover interval points to a shortage of beds whereas a long interval may indicate an excess of beds or a defective admission mechanism

76. POPULATION CHANGE AND DOUBLING TIME Population change has three components Birth Death Migration (In - Out) Population change= (Birth-Death) + (In migration-Out migration) Rate of population growth(r) = CBR-CDR This rate is sometimes called crude rate of natural increase because its computation is based on crude rates

77. POPULATION PROJECTION is a statement about what the size and age composition of the population would be at a given future time if the fertility , mortality and migration were to follow certain specific trends based on this rate of increase(r), the population (Pt) of an area with current population size of (Po)can be projected at some time t in the short time interval (mostly not more than 5 years) using the following formula

78. POPULATION PROJECTION Reading assignment Pt= P o (1+ r) t OR Pt=P o r t - the exponential projection formula POPULATION DOUBLING TIME ???? The doubling time of the size of population can be estimated based on the formula for projecting the population From the formula we want to find out the time t at which the current population Po will be 2 Po. Therefore, => read from you hand out

79. Thank you!!!