DEMANDS FOR AND PROVISION OF
CENSUS MICRO DATA:
THE SRI LANKAN EXPERIENCE
Vasana Jayakody
Department of Census and Statistics
Sri Lanka
The power of Micro data


Aggregate tables can be likened to a postcard
where the originator decides what scene to show
the viewer….
Micro data file can be likened to a camera where
the viewer can decide which scene is of most
interest before they snap the picture…
Ernie Boyco
Statistics Canada
Overview

Introduction
 Sri
Lankan national statistical system
 Legal authority
 Censuses of Population and Housing

Release of micro data
 Current
practice
 Issues in releasing Census micro data


Archiving micro data
Way forward…
Introduction – National Statistical System
A centralized system
 DCS has the co-ordinatory and technical supervisory
authority
 Legal authority is vested with the DCS
Among DCS responsibilities are;

 Establishment
and maintenance of statistical standards,
coding and classification schemes
 Provision of trained statistical cadres required by the
national statistical system
Introduction – National Statistical System

Before gaining independence in 1948
Statistics were compiled as by-products of administrative
records by individual departments or
 Collected by separate Census Units/ Statistical branches
with little or no coordination


After 1948
The Department of Census and Statistics (DCS) was formed.
 The official statistical system began to develop in a coordinated and systematic manner to meet the growing
demand for comprehensive and reliable statistics by
planners and policy makers.

Introduction – National Statistical System

1951 and afterwards
 The
then Prime Minister issued a directive in 1951 that
it is the responsibility of DCS to provide all statistical
information required by government departments.
 Statistical branches were established in key ministries
and government departments.
 Statistical units were set up in all 25 districts throughout
the country.
Legal authority
2 Ordinances under which the DCS collects data.
 Census
Ordinance
 Statistics Ordinance
Established to secure the reliability and thereby the
usefulness of statistics by ensuring the protection of
the privacy of the respondents.
Legal authority – Census Ordinance



First in 1868 – under English Law
Repealed in 1900 (drafted on the lines of the Indian
Census Act). This has substantially became the basis for
Census taking in Sri Lanka with minor amendments in
subsequent censuses.
The Census Ordinance casts an obligation on the part
of the respondents to answer all questions asked at the
Census, and at the same time safeguards the
respondents by causing any information collected at a
census, to be inadmissible as evidence in a court of law.
Legal authority - Statistics Ordinance





Was enacted in 1935 and amended in 1955.
Provides for the establishment of an official bureau of
Statistics.
Provides legal sanction for the DG of Census to collect
statistical information.
Safeguards the confidentiality of information provided by
the respondent.
Prevents the disclosure or arrangement of data to facilitate
the identification of any particulars as being information
related to any individual persons or business, in any report,
summary of statistics or other publications prepared based
on the data collected under the Statistics ordinance.
Censuses of Population and Housing





First scientific Population Census in 1871. Usually in
every 10 years with certain exceptions.
No census in 1991 due to the disturbances prevailed in
the Northern/Eastern parts of the country.
Only 18 (out of 25) districts were covered in 2001.
CPH2012 is the 14th decennial Census.
Special significance as the first Census to cover the
entire country since 1981 (after 31 years).
CPH2012
Traditional Census which was conducted in 3 main stages.
New technologies were used at all possible stages.
Mapping Operation
Use of satellite images, GPS to demarcate and draw
Census Block Maps.
Listing Operation
Buildings in all 65,000 CBs were labeled, numbered
and listed and the “Master Register of Census Blocks”,
the Census Monitoring System was prepared.
Census Enumeration
Was conducted between 27 February – 20 March
2012.

Online Census on pilot basis (in selected condominiums in Colombo)
New technologies – Post enumeration

Data Processing
 Data
capture using OMR, ICR
 Computer Assisted Coding of Occupation and Industry
 Imputations

Data Dissemination
 Interactive
visualizations (QuickStats)
 Interactive online databases (REDATAM)
Release of micro data – current practices


Dissemination of census data in the form of micro
data poses challenges as the DCS is bound to
safeguard the right to privacy of the respondents
and any breach of privacy would lead to loss of
trust of the respondents leading to non-cooperation
in future census taking exercises.
DCS, therefore, has been cautious in disseminating
data in the form of micro data and has formulated
its policy on micro data dissemination with strict
adherence to the statistics ordinance.
Release of micro data – current practices



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Micro data of Censuses is not released.
Micro data of sample surveys are released free of
charge to selected users (Requests of only government
institutes, recognized universities, students engaged in
higher education, selected international agencies are
entertained).
Should submit the study/project proposal.
Only 25% of the data file at the first stage and the full
data file is considered after reviewing the draft report
prepared on the 25% sample.
Should sign an agreement assuring confidentiality when
handling/storing micro data.
LankaDatta – the National Data Archive

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LankaDatta, the National Micro data Archive, was started
in 2008.
The repository for non official datasets as well.
Technical and financial assistance - Accelerated Data
Program from the World Bank and PARIS21
Tools/ guidelines was provided by the International
Household Survey Network. Data Documentation Initiative
(DDI) metadata standard is used in LankaDatta.
The DCS is responsible of acquisition, documentation,
anonymisation, dissemination and preservation of micro
data and related metadata.
Way forward….
Currently investigating the possibilities of improving
the Census micro data dissemination methodology.
Options being investigated

 Licensed
census micro data files for bona fide users
 Data enclave in the DCS head office
 Remote data access – REDATAM+SP
Way forward….
Issues that are looked into;
 Whom
should the Licensed files be made available to
 Appropriate sample size for release
 Who can access data at the Data Enclave
 Should current annonymization methods be changed
 Timing of micro data release
 Additional costs and how they are recovered
 Possible logistic issues
Thank you………