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Optimum sampling strategy for

National Households In Abu Dhabi

(The Household Master Sample 2012)

Authors :Mohammed Al Rifai (Ph.D.) Mariam Al Qemzi

10/ October/2014

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Contents

Introduction

Problem Identification

The Structure of Abu Dhabi Sampling Frame

Master Sampling Frame and Stratification

Stratification by Ratios of National Households

Master Sample Size and Allocation

Modified Allocation Criteria By Nationality Strata

Conclusion

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The Emirate of Abu Dhabi

•Almost 43 years since the formation of the UAE.

•UAE comprises Abu Dhabi plus six other Emirates.

•Abu Dhabi accounts for over 80 per cent of UAE land mass.

•Abu Dhabi contains around one third of UAE population.

•Emirati citizens make up around 20 per cent of Abu Dhabi

population.

•Abu Dhabi oil represents around 10 per cent of global reserves.

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Introduction

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Statistics Centre – Abu Dhabi

•SCAD is the official source of statistical data for Abu Dhabi.

•Our Mission:

1 .Develop and organize a statistical system in the Emirate.

2 .Provide relevant and reliable official statistics serving policy makers, the

business community and the public .

• Celebrated five years of operation in April 2014.

• Operates in accordance with international best practice to provide range of statistics.

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Introduction

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How to improve the sample strategy for national households, to ensure precise and highly accurate estimates.

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National 22%

Non National 60%

Shared18%

Households Type

Problem Identification

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The Structure Of Abu Dhabi Sampling Frame

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Abu Dhabi three regions:

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The Structure Of Abu Dhabi Sampling Frame

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Abu Dhabi Emirate

Regions (3)

Districts (117)

Sectors (1000)

EA (1883)

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The Structure Of Abu Dhabi Sampling Frame

Region Total No. EAs% All

Households% National

Households

% Non National

Households

% Shared Households

Abu Dhabi 1,215 64.4 58 70.2 52.8

Al Ain 551 29.2 37 23.6 38.4

Al Gharbia 117 6.4 5 6.2 8.7

Total 1,883 100 100 100 100

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Master Sample Frame and Stratification

In 2012 Master sample:

• Key Domains of Analysis:

– Region– Citizenship

• Levels of stratification of EAs:

9

Level 1

•Geographic domains which

are the three regions of Abu

Dhabi Emirate

Level 2

•Concentration of National

households within each

region

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Stratification by Ratios of National Households

The nationality strata are as follows:

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Stratum Concentration of

National Households Total No. of EAs

%National Households for the

stratum

%All Households

1 0 to 24.9% 1,315 7.3 69.9

2 25 to 49.9% 255 35.8 13.1

3 50 to 74.9% 199 61.7 11.1

4 75% or more 114 83.7 5.9

Total 1,883 21.5 100

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Master Sample Size and Allocation

Master Sample size:

Number of PSUs in the master sample should be sufficiently large to provide sample households for:

• Household surveys that are currently planned.

• Future Surveys – may require larger samples

• 4 Replicates.

Result - A sample of 560 EAs. This represents nearly 30% of all EAs used in Census 2011.

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Master Sample Size and Allocation

Master sample allocation:

Allocation by region based on:– previous sampling errors for key estimates of households surveys .– 4 Replicates

EA allocation:

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EA count Region

320 Abu Dhabi

160 Al Ain

80 Al Gharbia

560 Total

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Modified Allocation Criteria By Nationality Strata

Proportional allocation adjusted by as an adjustment factor ;

• The modified allocation criteria can be expressed as follows:

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4

1hhh

hhh

WK

WKnn

Where:

nh = number of sample EAs allocated to stratum h.

n = total number of sample EAsWh = weight assigned to nationality stratum h ;

Nh = total number of households in nationality stratum h

N = total number of households in frame

hK

4,...,1;41 hKh

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Modified Allocation Criteria By Nationality Strata

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4 3 2 1 Stratum

75 – 100% 50 - 74.9% 25 - 49.9% 0 – 24.5% EAs by National groups

5.9% 11.1% 13.1% 69.9% % of All households

83.7% 61.7% 35.8% 7.3% % National households

4 3 2 1 Adjustment factor

The expected ratio of the national household in the sample Percentage of national households in the stratum (h)Wh : weight assigned to nationality stratum h ;

: Adjustment factor,

hK

hW

hR

4

14

1

h

h

hh

hhh

WK

RWKp

hK 4,...,1h

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Conclusion

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• % National Households using proportional Allocation: 21.5%

• % National Households using Modified Allocation: 35.6%

• Implementation: high level of precision in LFS2012

Sample EAs by Region and Nationality Strata

RegionNationality Stratum Estimated %

National Households in SampleTotal 1 2 3 4

Abu Dhabi 320 155 58 67 40 33.3%

Al Ain 160 65 23 39 33 40.6%

Al Gharbia 80 39 22 10 9 29.9%

Total 560 259 103 116 82 35.6%

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• For more information please read the paper.• Website: www.scad.ae• Authors:

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Contact

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