Organised by United Nations Statistics Division (UNSD) in conjunction with the African Centre for...

Organised byOrganised by

United Nations Statistics Division (UNSD) in United Nations Statistics Division (UNSD) in conjunction with the African Centre for Statistics conjunction with the African Centre for Statistics Addis Ababa, Ethiopia, 14 – 18 September 2009Addis Ababa, Ethiopia, 14 – 18 September 2009

Workshop on 2010 World Programme on Workshop on 2010 World Programme on Population and Housing Censuses: Census Population and Housing Censuses: Census Evaluation and Post Enumeration SurveysEvaluation and Post Enumeration Surveys

Country ExperienceCountry ExperiencePresented byPresented by

Mrs. N.GujadhurMrs. N.Gujadhur

Central Statistics OfficeCentral Statistics OfficeMauritiusMauritius

September 2009September 2009

Islands of Mauritius and Islands of Mauritius and RodriguesRodrigues• Capital: Port LouisCapital: Port Louis

• Population : 1.28 mnPopulation : 1.28 mn

• Population growth rate: Population growth rate: 0.5%0.5%

• Area: 2,040 km2Area: 2,040 km2

• Population density: 625 Population density: 625 persons/km persons/km22

• Monetary unit: MRupees Monetary unit: MRupees

• Literacy rate : 85%Literacy rate : 85%

• Languages: English & Languages: English & FrenchFrench

• Census taking in MauritiusCensus taking in Mauritius

• Evaluation of the 2000 CensusEvaluation of the 2000 Census

• Previous Census evaluationsPrevious Census evaluations

• Census ErrorsCensus Errors

• Demographic Methods for census evaluationDemographic Methods for census evaluation

OutlineOutline

• 1st complete Census in the Island of Mauritius was 1st complete Census in the Island of Mauritius was undertaken in 1735undertaken in 1735

• Since then, censuses have been taken in 1846, 1851 Since then, censuses have been taken in 1846, 1851 and every 10 years up to 1931.and every 10 years up to 1931.

• After the 2nd World War, the ten-yearly programme After the 2nd World War, the ten-yearly programme was resumed and Housing and Population censuses was resumed and Housing and Population censuses were undertaken in:were undertaken in:

1952, 1962, 1972, 1952, 1962, 1972, 1983, 1990 and 2000 1983, 1990 and 2000

• Next census => 2011Next census => 2011

Census taking in Mauritius Census taking in Mauritius

Census OrganisationCensus Organisation

The 2000 Housing & Population Census (HPC) was The 2000 Housing & Population Census (HPC) was conducted in the Island of Mauritius, Rodrigues and conducted in the Island of Mauritius, Rodrigues and Agalega.Agalega.

• 1st round - Housing Census1st round - Housing Census– Chief Enumerators enumerated all buildings, housing Chief Enumerators enumerated all buildings, housing

units, households, commercial establishments, hotels, units, households, commercial establishments, hotels, institutions etc.institutions etc.

• 2nd round - Population Census 2nd round - Population Census – Enumerators enumerated all persons present on census Enumerators enumerated all persons present on census

night as well as usual residents who were away on night as well as usual residents who were away on census night.census night.

2000 Census Data Evaluation2000 Census Data Evaluation

Census EvaluationCensus Evaluation Main objectivesMain objectives

• To identify the types & sources of errorsTo identify the types & sources of errors

• To measure accuracy of dataTo measure accuracy of data

• To adjust the data where necessaryTo adjust the data where necessary

Different methods of evaluationDifferent methods of evaluation• Matching studies - e.g Post Enumeration SurveysMatching studies - e.g Post Enumeration Surveys

• Non-Matching studiesNon-Matching studies

Mauritius => Census evaluation through Mauritius => Census evaluation through Demographic methods using previous censuses Demographic methods using previous censuses and comparisons with administrative data.and comparisons with administrative data.

• Previous Demographic Census EvaluationPrevious Demographic Census Evaluation

11stst census for which data evaluation was carried out => census for which data evaluation was carried out => 1952.1952.

1962 and 1972 => census evaluated by Experts appointed 1962 and 1972 => census evaluated by Experts appointed under the UN Programme of Technical Co-operation.under the UN Programme of Technical Co-operation.

1983 and 1990 => census evaluated by local staff under 1983 and 1990 => census evaluated by local staff under the guidance of UNECA Expert.the guidance of UNECA Expert.

2000 census => census data evaluation were carried out 2000 census => census data evaluation were carried out by local staff. by local staff.


• Census ErrorsCensus ErrorsCensus => massive data collection, errors may creep in Census => massive data collection, errors may creep in

at any stage of data collection and processing. at any stage of data collection and processing.

• These errors are:-These errors are:- (i) Coverage Error => error in the count of persons (i) Coverage Error => error in the count of persons /housing units /housing units (ii) Content Error => error in the recorded (ii) Content Error => error in the recorded

characteristics of those characteristics of those persons persons that were that were enumerated in the enumerated in the CensusCensus


• (i) Coverage Error(i) Coverage Error

• Coverage Error => non-sampling error that may have Coverage Error => non-sampling error that may have occurred during 2000 Census.occurred during 2000 Census.

Omission - Omitting a unit that should have Omission - Omitting a unit that should have been included. been included.

Duplication - Including a unit more than once.Duplication - Including a unit more than once.

Erroneous - Including a unit that should not Erroneous - Including a unit that should not have been included. have been included.


• Demographic methods used in Mauritius Demographic methods used in Mauritius for detecting coverage error - C2000for detecting coverage error - C2000

1. Balancing equation by sex1. Balancing equation by sex 2. Growth rate2. Growth rate 3. Age and sex composition 3. Age and sex composition 4. Sex ratio4. Sex ratio 5. Child-woman ratio5. Child-woman ratio 6. Population Estimates6. Population Estimates 7. External consistency checks7. External consistency checks


• 1. 1. Balancing equation by sexBalancing equation by sex Comparing the 2000 Enumerated Population with the Comparing the 2000 Enumerated Population with the

Expected population based on the 1990 census.Expected population based on the 1990 census.

So, when compared to international norms, a net deficit of 0.4% is acceptableSo, when compared to international norms, a net deficit of 0.4% is acceptable ..

Expected 2000Population

Enumerated Population -2000 Census

Excess of Enumerated over expected

1990 Enumerated Pop. 1,056,660

1990 - 2000

+ Live Births 211,689

- Deaths (75,425)

+ Arrival of Mauritian Residents 1,111,526

- Departure of Maurt. Residents (1,120857)

Expected Population-Year 2000 1,183,773

Enumerated Population 1,178,848

Excess - Enumerated /Expected -4,925 (-0.4%)


• 2. 2. Growth RateGrowth Rate Inter-censal growth rates can also help in the evaluation of Inter-censal growth rates can also help in the evaluation of

census data. census data. A low rate of growth would be suggestive of net under A low rate of growth would be suggestive of net under

enumeration in the 2enumeration in the 2ndndcensus relative to the 1census relative to the 1stst census or census or over enumeration of the 1over enumeration of the 1stst census relative to the 2 census relative to the 2ndnd census.census.

In Mauritius, the natural Growth rate shows a smooth In Mauritius, the natural Growth rate shows a smooth decline over time.decline over time.

Inter -censal period

Net Growth

Rate (%)

Natural Growth Rate(%)

1962 - 1972 1.97 2.39

1972 - 1983 1.48 1.81

1983 - 1990 0.79 1.30

1990 - 2000 1.10 1.22


• 3. 3. Age and sex CompositionAge and sex Composition The age and sex distribution (%) of the population for The age and sex distribution (%) of the population for

different censuses is also used to compare the Enumerated different censuses is also used to compare the Enumerated Population. Population.

A decrease in the proportion of children aged(0–4) andA decrease in the proportion of children aged(0–4) and

(5 –14) and a general increase in the proportion aged 60 (5 –14) and a general increase in the proportion aged 60 years and above can be observed from one census to another. years and above can be observed from one census to another.

Age Group

Census

1972 (%)

1983 (%)

1990 (%)

2000 (%)

0 - 4 12.4 11.7 9.2 8.0

5 - 14 28.0 20.8 20.5 17.2

15 – 44 42.7 49.6 51.1 50.8

45 – 59 11.0 10.9 10.9 14.9

60+ 5.9 7.0 8.3 9.1


• 3.3. Age and Sex Composition Age and Sex Composition (cont’d)(cont’d)

A Population Pyramid showing the 1990 and 2000 % A Population Pyramid showing the 1990 and 2000 % population by age and sex.population by age and sex.


• 4. Sex ratio4. Sex ratio The sex ratio is defined as the number of males per 100 The sex ratio is defined as the number of males per 100

females. It measures the composition of the population females. It measures the composition of the population enumerated at a particular age with respect to sex. enumerated at a particular age with respect to sex.

Unless affected by errors, the sex ratio of the enumerated Unless affected by errors, the sex ratio of the enumerated census population, should be relatively stable from one census population, should be relatively stable from one census to another.census to another.

Significant departures from this pattern would indicate Significant departures from this pattern would indicate coverage error in the enumerated population. coverage error in the enumerated population.

Census Year

1962 1972 1983 1990 2000

Sex ratio 100.8 100.2 99.2 99.8 98.1


• 5. Child Woman ratio5. Child Woman ratio The Child-woman ratio is defined as the number of The Child-woman ratio is defined as the number of

children aged 0-4 years per 1,000 women in the age group children aged 0-4 years per 1,000 women in the age group 15 – 44 years.15 – 44 years.

The child–woman ratio are in line with the fertility decline The child–woman ratio are in line with the fertility decline registered over the past decades. registered over the past decades.

1983 1990 2000

Republic of Mauritius

473.7 363.3 316.7


• 6.6. Population EstimatesPopulation Estimates This method of evaluation entails the projection of the 1This method of evaluation entails the projection of the 1stst

census forward in time to the 2census forward in time to the 2nd nd census based on estimated:census based on estimated:

– mortality ratesmortality rates

– fertility ratesfertility rates

– net migration ratesnet migration rates

These rates were applied to the 1990 Population Census and the These rates were applied to the 1990 Population Census and the expected population derived in this manner was then compared expected population derived in this manner was then compared with the 2000 enumerated population. with the 2000 enumerated population.


• 7. External Consistency Checks(i) Vital Registration System

Mauritius has a very good vital registration system. Counts of persons derived from Civil Status Division of Mauritius is complete, and provide valuable information on the accuracy of the census enumeration.

Births and deaths registration has been used to assess census coverage of the population at youngest ages, which are usually under-enumerated.

For the 2000 Population Census, adjustments for the under-enumeration of young children aged 0-9 ( 4,456 male and 3,569 female) were made to compensate this population coverage.


(ii) Education StatisticsComparison of Population Census with education statistics

is another external source of data with which Census data was compared.

Data from the 2000 survey conducted in March by the Ministry of Education was compared with census data on students currently going to school.

Male Female

Age Group

2000 Census Data

School Statistics

% Difference

2000 Census Data

School Statistics

% Difference

5 - 9 52,702 56,172 -6.2 51,860 55,147 -6.0

10 - 14 44,862 43,104 4.1 44,222 42,770 3.4

15 - 19 25,952 23,192 11.9 25,635 23,095 11.0

5 - 19 123,516 122,468 0.9 121,717 121,012 0.6


(iii) Housing Census Count Comparison of Population Census with Housing Census count

Housing Census was conducted from February to April 2000 Population Census was taken at the beginning of July

2000. 2000 Housing Census -February-April

2000 Population - July

% Difference

Private Households

297,881 296,832 0.4

Population 1,168,495 1,165,570 0.3

Thus, minor differences of around 0.3% in the population figures and 0.4% in the household figures are observed.


• Content ErrorsContent Errors Age profile of the population is one of the basic information. It Age profile of the population is one of the basic information. It

is therefore very important to evaluate the accuracy of the age is therefore very important to evaluate the accuracy of the age distribution. distribution.

• (i) Digit Preference(i) Digit Preference Digit preference or age heaping is a common error that Digit preference or age heaping is a common error that

occurs in the age reporting.occurs in the age reporting.

It appears that there is a slight preference for the digit 0 among both It appears that there is a slight preference for the digit 0 among both males and females.males and females.


• (i) Digit Preference (cont’d)(i) Digit Preference (cont’d)The table below shows the most preferred digits by sex -The table below shows the most preferred digits by sex -

1990 & 2000 Censuses1990 & 2000 Censuses

It is observed that preference for digit 0 has persisted It is observed that preference for digit 0 has persisted from 1990 to 2000 Census. However, the preferred digit from 1990 to 2000 Census. However, the preferred digit has shifted from 5 in 1990 to 2 in 2000 for female.has shifted from 5 in 1990 to 2 in 2000 for female.

Census Year

Index Republic of Mauritius

Male Female

1990 Myer’s 0,5 5,0

P.P.I 0,5,6 5,0,2

2000 Myer’s 0 0,2

P.P.I 0,9 0,2


• (i) Digit Preference (cont’d)(i) Digit Preference (cont’d)

The table below shows Indices for digit preference -1990 The table below shows Indices for digit preference -1990 & 2000 Censuses& 2000 Censuses

Both the Myer’s Index and the Preference Pattern Index Both the Myer’s Index and the Preference Pattern Index (PPI) show no marked digit preference in age reporting at (PPI) show no marked digit preference in age reporting at the Census. (0 = no digit preference & 180 for absolute the Census. (0 = no digit preference & 180 for absolute digit preference)digit preference)

Digit

Republic of Mauritius

Male Female

Myer’s

P.P.I Myer’s P.P.I

2000 Index

2.0 2.3 1.9 2.1

1990 Index

2.4 2.9 2.9 3.3


(ii) Vertical consistency checks for age-reporting errorTo quantify the degree of age - sex reporting errors,

various indices such as the Age Ratio Score; the Sex Ratio Score and the UN Age-Sex Accuracy Index/UN Joint Score have been calculated for the population aged under 70 years.

The census data is considered to be “accurate”, inaccurate” or “highly inaccurate” depending on whether the UN Age-Sex Accuracy Index is under 20, 20 - 40 or 40 and over respectively.

Thus, the 2000 census data was considered as accurate.

UN Age - Sex Accuracy Index

Census 1990 2000

UN Joint Scores

17.3 18.3


Cohort survival ratios Overall survival ratios

Age Male Female Age Male Female

0-4 0.9719 0.9842 0+ 0.9130 0.9369

5-9 0.9815 0.9848 5+ 0.9051 0.9309

10-14 0.9639 0.9944 10+ 0.8957 0.9244

15-19 0.9495 0.9809 15+ 0.8852 0.9140

20-24 0.9531 0.9864 20+ 0.8753 0.9041

25-29 0.9615 0.9698 25+ 0.8600 0.8891

30-34 0.9598 0.9724 30+ 0.8345 0.8704

35-39 0.9479 0.9718 35+ 0.7986 0.8441

40-44 0.9225 0.9618 40+ 0.7492 0.8071

45-49 0.8777 0.9326 45+ 0.6941 0.7636

50-54 0.8288 0.9091 50+ 0.6389 0.7182

55-59 0.7495 0.8504 55+ 0.5744 0.6609

60-64 0.6431 0.7586 60+ 0.5034 0.5970

65-69 0.5350 0.6843 65+ 0.4174 0.5175

70-74 0.3988 0.5501 70+ 0.3122 0.4083

75+ 0.2211 0.3065 75+ 0.2211 0.3065

All ages 0.9130 0.9369

(iii) Diagonal consistency checks The quality of census data can also be assessed by the analysis of cohort

survival ratios.

The cohort survival ratio is the ratio of the population of a particular age group at a given census to the population ten years younger in the preceding census. The survival ratio is expected to decrease smoothly with increasing age.


Thank youThank you

For additional information, go to:http://www.gov.mu/portal/sites/ncb/cso/report/hpcen00/census3/

index.htm

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