+ All Categories
Home > Documents > European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

Date post: 31-Dec-2015
Category:
Upload: marcella-quintin
View: 28 times
Download: 0 times
Share this document with a friend
Description:
European Conference on Quality in Official Statistics Session 26: Quality Issues in Census. «. Quality Assurance and Control Programme in the 2011 Population and Housing Censuses in Portugal. «. Carlos Dias Statistics Portugal. Rome, 10 July 2008. 1. «. - PowerPoint PPT Presentation
24
European Conference on Quality in Official Statistics Session 26: Quality Issues in Census « Rome, 10 July 2008 « Quality Assurance and Control Programme in the 2011 Population and Housing Censuses in Portugal « 1 Carlos Dias Statistics Portugal
Transcript
Page 1: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

European Conference on Quality in Official Statistics

Session 26: Quality Issues in Census«

Rome, 10 July 2008

«

Quality Assurance and Control Programme in the 2011 Population and Housing Censuses in Portugal

«

1

Carlos Dias Statistics Portugal

Page 2: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

2 «Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal «

Summary

1.Introduction;

2.Control of the processes;

3.Post Enumeration Survey;

4.Conclusions.

«

Page 3: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

3 «

«1. Introduction

Due to dimension and complexity, Census are surely the largest statistical operations in the world.

Statistical units enumerated in 2001 Census in Portugal:

Buildings ( 3 177 860);

Dwellings (5 046 544);

Households ( 3 650 757);

Persons ( 10 356 117).

Fieldwork activities involved around 28 500 people. «

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

}74,3 millions of pages (A4 format): more than 200 tonnes of paper

Page 4: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

4 «

«1.Introduction

In Census operations, the correct planning, organization and resource management of its different stages (since preparation to execution and dissemination) is the key factor for its success.

It is also important to define:

• measures of quality control to minimize the sprouting of errors;

• measures of evaluation and quantification of errors to check the data production. «

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 5: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

5 «

«

1. Introduction

In this scope, quality control and evaluation are fundamental tasks and are ways to assure that final results will respect the principles of statistical information:

Relevance;Accuracy;Timeliness;Accessibility;Comparability;Coherence. «

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 6: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

6 «

«

1.Introduction

Challenge to the 2011 CensusTo assure the implementation of a quality

assurance and control programme of both processes and data, in order to guarantee that the productive process is able to detect any inconsistencies and errors in time and for the final results to tend towards unquestionable quality.

«

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 7: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

7 «

«

1.Introduction

Profiting by the success of the model adopted in 2001, the programme to be implemented in 2011, will be based on two great areas:

Control of the processes;

Post Enumeration Survey.

«

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 8: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

8 «

«

2. Control of the processes

The implementation and results of the Quality Assurance and Control Programme will be oriented and audited by a highly respected university institution in the statistical area.

The control of the processes will include implementation of mechanisms for checking and control applied to some key points of the productive process, so that the quality of the data collection and treatment are ensured and under permanent control.

«

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 9: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

9 «

«

2. Control of the processes

For 2011 Census is planned the implementation of evaluation procedures as well as the quality control in the following sub-processes:

2.1. Selection, training and technical evaluation;

2.2. Fieldwork control;

2.3. e-Census system;

2.4. Data processing.

«

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 10: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

10 «

«

2. Control of the processes

2.1. Selection, training and technical evaluation of regional and local participants;

Selection tests for training candidates;

Definition of the training programme;

Technical models for the evaluation of acquired knowledge;

Models for the control of practical training;

Control the training period. «

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 11: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

11 «

«

2. Control of the processes

2.2. Fieldwork control

Delivery and collection of questionnaires – as a nuclear and decisive task for guaranteeing the Census quality, we foresee the implementation of two types of control instruments:

Individual control - verification and evaluation of the performance of each person involved during the Census process.

«

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 12: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

12 «

«

2. Control of the processes

2.2. Control of the fieldwork

Alert Indicators System – will control information quality during the enumeration that allows correction of eventual inconsistencies. It consists of monitoring just in time some results (during the enumeration phase) by comparing them with the expected values, and having as reference other information sources (e.g. administrative registers). Whenever deviations are detected it is activated an additional checking procedure in the fieldwork.

Information system on persons;

Information system on dwellings;

«

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 13: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

13 «

«

2. Control of the processes

2.3. e-Census System

In 2011, Statistics Portugal plan to implement, for the first time, an on-line response system.

Control and evaluation of the quality applied to e-Census system (Internet return of forms) – evaluation instruments will be developed, taking into consideration the coverage checking on the 3 alternatives: web response versus paper questionnaires versus non response. «

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 14: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

14 «

«

2. Control of the processes

2.4. Data processing

It will be developed instruments allowing evaluation of quality related to:

ICR (Intelligent Character Recognition) processes;

Automatic codification system;

Correction system.

«

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 15: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

15 «

«3. Post Enumeration Survey (PES)

The PES will start soon after the end of enumeration phase, in an autonomous way and oriented to a sample of dwellings.

The PES will not have impact in the 2011 Census databases, and will allow measuring the census data quality, by quantifying errors (both of coverage and content).

As happened in 2001, the sample extraction and control will be oriented to an external entity’s responsibility to ensure that the results are properly audited and to strengthen the credibility of this survey.

«

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 16: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

16 «

«3. Post Enumeration Survey (PES)

The PES is the true instrument of the final measurement of the quality of the 2011 Census, and for this reason, special care should be taken with it, both in preparation and in carrying it out.

Objectives:

Evaluation of errors in gross and net coverage of each statistical unit observed;

Evaluation of content errors in variables and their respective modalities for each statistical unit. «

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 17: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

17 «

«

3. Post Enumeration Survey (PES) - Main methodology characteristics of the PES

The sampling used in this survey will be multi-stage and will represent every one of the statistical units and the main characteristics of each, at the NUTS 2 level (7 regions);

The collection of data for the 2nd enumeration will be carried out after the collection of the data for the first enumeration is concluded, by a different person and one who is unknown to the person who carried out the first enumeration;

Whereas the evaluation of coverage includes all of the statistical units enumerated in the same area, the content evaluation only includes those statistical units enumerated in both.

«

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 18: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

18 «

«3. Post Enumeration Survey – Coverage

evaluation

«

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

STATISTICAL UNIT

TOTAL

(%)

TOTAL X1 100

CORRECTLY X2 X2/X1*100

ENUMERATED IN

CENSUS UNCORRECTLY X3 X3/X1*100

TOTAL X4 X4/X1*100

ENUMERATED IN PES NOT OBSERVED IN CENSUS X5 X5/X1*100

GROSS DIFFERENCE BETWEEN CENSUS AND PES

[(X1-X4)/X1]*100

NET DIFFERENCE BETWEEN CENSUS AND PES

[(X3+X5)/X1]*100

Page 19: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

19 «

«

3. Post Enumeration Survey – Content errors

«Content errors

Wrong or inconsistent declarations

Omission of information due to bad performance of the enumerator or incorrect interpretation of the questionnaire

Unfamiliarity, confusion and resistance relatively to the answer

Processing of the information: edition and imputation of missing data

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 20: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

20 «

«

3. Post Enumeration Survey – Content evaluation

«

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

VARIÁBLE: Attended school

Census

PES

Never

attended Attending Attended

Units

correctly

included

TOTAL

Never attended n11 n12 n13 n11 n1.

Attending n21 n22 n23 n22 n2.

Attended n31 n32 n33 n33 n3.

Units correctly included n11 n22 n33 nij, i=j

TOTAL n.1 n.2 n.3 n

Page 21: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

21 «

«

3. Post Enumeration Survey – Content evaluation

«

Based on a matrix of this type, the content errors of each variable should be calculated by the formula

n

nce

m

jiij 1

^ m=number of modalities of the variable;

n= number of answers to the variable in Census and PES

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 22: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

22 «

«

3. Post Enumeration Survey – Content evaluation

«

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

VARIÁVEL: Attended school Modality: Attended

Census

PES

With the

modality "

Attended"

Without the

modality

"Attended"

TOTAL

With the modality " Attended" a b a+b

Without the modality

"Attended"

c d c+d

TOTAL a+c b+d n

Page 23: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

23 «

«4. Conclusions

Program of control and evaluation of the quality of the Censuses involves complex challenges that will need customized solutions.

To assure the implementation of a quality assurance and control programme of both processes and data, in order to guarantee that the productive process is able to detect any inconsistencies and errors in time and for the final results to tend towards unquestionable quality.

The implementation and results of the Quality Assurance and Control Programme will be oriented and audited by a highly respected university institution in the statistical area. The sample extraction and control will be oriented to another external entity’s responsibility to ensure that the results are properly audited and to strengthen the credibility of this survey.

«

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal

Page 24: European Conference on Quality in Official Statistics Session 26: Quality Issues in Census

24 «

«

Thank you for your attention

[email protected]

«

Quality Assurance and Control Programme in the 2011 Censuses Population and Housing in Portugal


Recommended