National Sample Survey Office (NSSO)

Statistical System In India

Ministry of Statistics and Programme Implementation

(MoS&PI)

MOS&PI has two Wings

I. Statistics Wing - National Statistical Organization (NSO)

Central Statistics Office (CSO)

National Sample Survey Office (NSSO)

II. Programme Implementation Wing

Statistical System In India

• Central Statistical Office (CSO): The main

responsibility assigned to the CSO is to bring about

coordination of statistical activities among various

statistical agencies in the Central Government and of

Statistical Bureaus of State Governments, which were

set up for similar coordination of activities of statistical

agencies at the State level.

• National Sample Survey Office (NSSO): The main

responsibility assigned to the NSSO is to collect data on

varied Socio-Economic subjects through nation-wide

sample surveys to create and update data base.

National Sample Survey Office (NSSO)

• The Directorate of National Sample Survey (NSS) came

into being in 1950 to collect information through sample

surveys on a variety of socio-economic aspects.

• The Directorate of NSS was assigned the job ofconducting the field work.

• The work relating to finalisation of sampling design,schedules of enquiries, writing of instructions, training offield staff, processing of data and writing of reports wasall entrusted to the Indian Statistical Institute.

National Sample Survey Office (NSSO)

• In March 1970, the Directorate of NSS was reorganised

and all aspects of its work were brought under a single

government organization called National Sample Survey

Organisation (NSSO) under the overall technical

guidance of Governing Council.

• After the formation of National Statistical Commission(NSC) on 01.06.2005, the Governing Council of NSSOwas dissolved and its work was taken over by NSC.

NSC constitution

• Chairman: Eminent statistician or social scientist.

• Part time members: 4 part time members having experience in

(i) Economic Statistics.,

(ii) Social and Environment Statistics.,

(iii) Statistical Operations such as Census/ Surveys

• The Secretary, Planning commission (ex-officio member)

• CSI.

THE PRESENT STRUCTURE

Ministry of Statistics&

Programme Implementation

National Statistical

Commission

NSSO

FODSDRD DPD CPD

Collection of data on varied Socio-Economic subjects

through nation-wide sample surveys to create and

update data base for use in:

-Policy formulation

-Programme implementation

-Programme evaluation

-Research & public debate and

-Economic & administrative decisions for national

development.

National Sample Survey Office

Basic Objective:

Organisational Structure

• The NSSO is headed by the DG & CEO.

• It is the largest survey organization of its kind with staff strength of about 5288 comprising 269 group A officers and 5019 other officials.

• The organisation has four divisions:

– Survey Design and Research Division (SDRD)

– Field Operations Division (FOD)

– Data Processing Division (DPD)

– Coordination & Publication Division (CPD)(Earlier called Economic Analysis Division)

NSC and National Sample Surveys (NSS)

• The NSSO functions under the overall guidance of the NSCand the Working groups constituted by it for each Round ofS.E. surveys.

• The NSC decides– Short and long term programmes including subjects to be

covered and periodicity– Methodological improvements in conduct of surveys

• Approves sample design, concepts and definitions, questionnaires, estimation procedure, tabulation plan, etc.

• Approves studies for improving survey methodology, data collection, processing and dissemination and other issues .

• Approves the survey reports for release• Constitute Expert Groups for any specific technical issue, if

necessary

Schedule of Surveys Ten Year Cycle

Consumer Expenditure and

Employment & Unemployment - Twice

Social Consumption (health, education etc.)

(generally 6 month survey) - Twice

Un-organised Manufacturing - Twice

Services Sector - Twice

Land & Livestock holdings

and Debt & Investment - Once

Open Round - Two years (For other surveys on demand)

Survey Design And Research Division (SDRD)

Located at Kolkata and headed by Addl. Director General

Major Functions

• Formulation of sampling design, concepts and definitions

• Drawing of survey schedules

• Instruction Manuals for field work

• Finalisation of Sample List

• Scrutiny and validation instructions i.e. FSP, PDES, CSP, HOWLER Pts. etc.

• Checking of Multipliers, draft tables

• Formulation of Tabulation plan

• Drawing up of Estimation Procedure

• Finalisation of survey results & Preparation of key reports

• Undertaking studies for the improvement of survey methodology

• Publication and distribution/ sale of NSS reports,

• Providing technical guidance on sampling techniques to various official agencies, etc.

• Secretarial assistance to the Working Group on NSS surveys

Field Operations Division (FOD) of NSSO

Hqrs. at New Delhi and Faridabad and headed by an

Addl. Director General.

The biggest Division of NSSO having a network of 175

offices spread throughout the length and breadth of the

country at 3-levels, viz.:

6 Zonal Offices

49 Regional Offices

118 Sub-regional Offices

Responsible for carrying out the field work of not only

the Socio-economic surveys but also for other surveys.

Activities of FOD

Besides carrying out the field work of Socio-

economic surveys, the FOD is also responsible for:

Carrying out the field work of Annual Survey of

Industries (ASI) on behalf of CSO;

Carrying out the supervision of agricultural surveys

conducted by State Agricultural Statistical Authorities

(SASA), on area enumeration and crop cutting

experiments;

Collection of Price Data for Consumer Price Index

(Urban) from Urban Centers, on behalf of CSO;

Collection of price data from rural centers for CPI for

Agricultural/ Rural Labourers compiled by Labour

Bureau; and

Carrying out the Urban Frame Survey (UFS), for a

frame for urban areas for Socio-economic surveys.

Field Problems in SE Survey

Length of schedules resulting in informant/

investigator fatigue

Arduous field conditions

Informants’ indifference/ reluctance

Informants tend to hide their income and

exaggerate their expenditure

Investigators are posted at a place where

local people’s language is not known to the

Investigator

To manage with contract investigators due to

large no. of vacancies in regular posts

Data Processing Division (DPD)

Located at Kolkata and headed by Addl. DirectorGeneral

Major Functions

To undertake data-processing and tabulation forvarious NSS rounds and other adhoc surveys.

• To provide technical assistance to the SSBs/ DESs forprocessing and tabulation of NSS State sample dataand also for pooling central and state sample data.

• To impart training on IT and data processing.

• To undertake special tabulation work for Ministries/Govt. Departments.

Activities of Data Processing

-Finalisation of sampling frame in consultation with SDRD

-Software development for generation of sample list as per

the design and drawing sample as per allocation

-Software development for data entry, verification and

validation for central and state sample

-Training Manual preparation (system design, data layout,

PDES and CSP points)

-PDES inconsistencies taken up with FOD

-Phase-I validation, CSP (Content check)

-Phase-II validation (Coverage check)

-Phase-III validation (Howler check)

-Software for estimation procedure and computation of

multiplier

-Generation of trial and final tables

-Dissemination of unit level data

Coordination & Publication Division (CPD)

Located at New Delhi and headed by a Dy. Director General

• Functions as technical secretariat for DG&CEO

• CPD is responsible for:

– Coordinating the activities of all the four divisions of NSSO

– Dissemination of survey results

– Publication of the biannual technical journal "Sarvekshana".

– Supplying survey data of various rounds to individuals, research scholars, research Institutions and other private and government bodies

– Liaison with other Departments/Ministries on various matters concerning NSSO.

– Dealing with Parliament questions.

• Deciding subject and formation of Working Group (WG)• WG deliberations

– Subject coverage, concepts and definitions, sampling design, draft survey instruments

• Finalisation of survey instruments– Training manual and survey instruments , – AITOT– Sample selection and dissemination of Sample List (Central and State

sample)– Tabulation plan and estimation procedure– Quality control instruments

• FSP, PDES, CSP, • Consolidated clarification on field queries post RTC • Reply of queries from field offices of FOD & DES on regular basis.

• Data validation– Computer Edit Programme (CEP), Trial tables, Final tables

• Report finalisation and Dissemination– First draft, in-house discussion, 2nd draft, draft circulation, assimilation of

comments, approval by NSC– printing, press release, release of report – Dissemination, sale and documentation

Different Activities during one Round of NSS

Subjects Coverage in recent PastNSS 71st round (Jan - June, 2014)

1.Social Consumption: Health and Education

NSS 70th round (Jan - Dec, 2013)

1. Land & Livestock holdings and Debt & Investment2. Situation Assessment of Farmers

NSS 69th Round (July - Dec, 2012)

1. Housing conditions, Drinking Water Supply & Sanitation and Hygiene

NSS 68th round (July, 2011 - June, 2012)

1. Employment & Unemployment 2. Household Consumer expenditure

NSS 67th Round (July, 2010 - June, 2011)

1.Unincorporated non-agricultural enterprises in manufacturing, trade and

other services sector (excluding construction)

Subject coverage for current round

NSS 72nd round (Jul 2014 - Jun 2015)

Consumer Expenditure, Domestic Tourism and Household Consumption of Durable Goods and Services

Data Users

• Planning Commission - Employment & Unemploymentand Household Consumer Expenditure.

• National Accounts Division, CSO - Employment &Unemployment, Household Consumer Expenditure,Unorganised Manufacturing, Unorganised Services,Debt & Investment.

• Reserve Bank of India - Debt & Investment.

• Ministry of Labour - Employment & Unemployment.

• Various other Ministries & Departments (Health,Education, Women & Child Development etc.) - SocioEconomic Surveys, Land & Livestock Holdings etc.

• Research Scholars (worldwide).

• UN Agencies (IMF, UNICEF, FAO etc.)

1

Basic Concepts of Survey Sampling Theory

2

Statistical Survey Sampling

Statistical Survey Sampling is a systematicapproach to selecting a few elements (a sample)from an entire collection of data (a population) inorder to make some inferences about the totalpopulation.

The sampling methods help us to ensure thatsamples represent the entire population.

A sample of fairly modest size is sufficient to givea reasonable idea of a much larger universe.

3

Advantages of Survey Sampling

less expensive

timeliness

wider range of survey data

wider choice of methods of observation,

measurement or questioning

results subject to smaller non-sampling

errors

4

Disadvantages of Survey Sampling

results of a sample survey are subject to

sampling errors.

a sample may seriously over-represent,

under-represent, or even fail to represent

infrequently-occurring subgroups of a

population.

results at disaggregated levels may not

be reliable.

5

Principal Steps in a Sample Survey

1. Objective of the Survey

2. Defining the Population to be Sampled

3. The Frame and Sampling Units

4. Selection of Proper Sampling Design

5. Data to be collected

6. The Questionnaire or Schedule

6

Principal Steps in a Sample survey (contd.)

7. Method of Collecting Information

(i) Interview Method

(ii) Mailed Questionnaire Method

8. Organisation of field Work

9. Treatment of non-response

10. The Pretest

11. Summary and Analysis of the Data(i) Scrutiny and editing of the data(ii) Tabulation of data(iii) Statistical analysis(iv) Reporting and conclusions

7

Sampling and Non-sampling Errors

The theory of survey sampling

includes a variety of sample selection

and estimation methods

its objective is to obtain a reasonably

representative sample

9

Methods of Sampling – three

broad categories

The three broad categories of methods

of sampling are

(a) Non-probability sampling

– Subjective or purposive or

judgment sampling

(b) Probability sampling

(c) Mixed Sampling

Sample Design specifies

i. the population to be surveyed, sample units to

adopt and different stages of selection if required

ii. sample selection method,

iii. sampling frame to use (list of units, maps of area),

iv. size of the sample,

v. stratification,

vi. allocation of size to different strata,

vii. statistic to be used

viii. treatment of non-response

ix. estimation procedure of sampling error.

11

Sample Selection Procedures / Schemes

Some of the common selection methods of

sample are:

a. Simple Random Sampling

b. Systematic Sampling

c. Stratified Sampling

d. Cluster Sampling

e Probability Proportional-to-size Sampling

f. Multi-stage sampling.

12

Stratified Sampling

In this sampling procedure, we divide the population into relatively homogeneous groups called Strata.

Then from each stratum randomly select a specified number of elements using any of the following two criteria:

Proportional allocation

Optimum allocation

Greater the difference in the stratum means, greater is the gain in precision of stratified sampling over un-stratified simple random sampling.

13

Allocation of Sample size

In proportional Allocation

ni = (n/N)*Ni

Or n1/N1 = n2/N2 ………= nk/Nk = n/N

In optimum allocation ni’s are chosen so as to(a) Maximise the precision for (i) fixed sample

size n or (ii) fixed cost

(b) Minimise the total cost for fixed precision

14

Advantages of Stratified Random Sampling

(i) More representative

(ii) Greater accuracy

(iii) Administrative convenience

(iv) Very useful in the fields of highly skewed distributions

Multistage Sampling

As the name suggests, multistage sampling refers to a

sampling technique, which is carried out in various stages.

Example:

If we are interested in obtaining a sample of households from

rural areas of a particular State, the first stage units may be

districts, the second staged units may be villages in the districts

and third stage units will be households in the villages.

Each stage thus results in a reduction of the sample size.

Contd….

• Multistage sampling consists of sampling first stage units by

some suitable method of sampling.

• From among the selected first stage units, a sub-sample of

secondary stage units is drawn by some suitable method of

sampling which may be same as or different from the method

used in selecting first stage units.

• Further stages may be added to arrive at a sample of the

desired sampling units.

Merits and Limitations of Multistage sampling

• Multistage sampling is more flexible as compared to other

methods of sampling.

• It is simple to carry out and results in administrative

convenience by permitting the field work to be concentrated,

yet covering large area.

• Most practical advantage of multistage sampling is that we

need the second stage frame only for those units which are

selected in the first stage sample.

• This leads to great saving in operational cost.

• However, a multistage sampling is generally less efficient

than a suitable single-stage sampling of the same size.

18

Sampling Design used in Socio-economic Surveys undertaken by NSSO

A stratified multi-stage sampling design is generally used in Socio-economic Surveys undertaken by NSSO.

The first stage units (FSU) are the Census Villages (Panchayat Wards in case of Kerala) in the Rural sector and Urban Frame Survey (UFS) Blocks in the Urban Sector.

The ultimate stage Units (USU) are households in both Rural & Urban Sectors.

In case of large FSUs, one intermediate stage of sampling is done by selecting two hamlet groups/ sub blocks from each of such rural/ urban FSU respectively.

NSS 72nd ROUND

(July 2014 – June 2015)

‘Consumer Expenditure’

‘Domestic Tourism Expenditure’

‘Household Expenditure on

Services and Durable Goods’

Sample Design 1

Schedules of enquiry

Schedule 0.0 List of Households

Schedule 1.60 Household Consumer Expenditure (4)

Schedule 1.61 Household Consumer Expenditure with details of Food Consumption (4)

Schedule 1.62 Household Consumer Expenditure with details of Non-Food Consumption (4)

Schedule 21.1 Domestic Tourism Expenditure (10)

Schedule 1.5 Household Expenditure on Services and Durable Goods (6)

Sample Design2

Coverage and sample design

Sample Design3

Geographical coverage

Whole of the Indian Union except thevillages in Andaman and NicobarIslands which remain extremelydifficult to access due to the restrictionimposed by local authorities

Sample Design4

Participation of States/ UTs

State/UT Extent ofmatching

Nagaland (U) triple

Andhra Pradesh, J & K , Manipur, Odisha, Delhi

double

Maharashtra (U) one and half

Remaining States/ UTs equal

Sample Design5

Work Programme and Sub-rounds

The survey will be of one year duration starting from1st July 2014 and ending on 30th June 2015.

Survey period will be divided into four sub-roundsof three months’ duration each, as follows:

sub-round 1 : July - September 2014

sub-round 2 : October - December 2014

sub-round 3 : January - March 2015

sub-round 4 : April - June 2015

Sample Design6

Work Programme and Sub-rounds

In each of these four sub-rounds equal numberof sample villages/ blocks (FSUs) will be allottedfor survey.

Because of the arduous field conditions, thisrestriction is not strictly enforced in Andamanand Nicobar Islands, Lakshadweep, Leh(Ladakh) and Kargil districts of Jammu &Kashmir and rural areas of Arunachal Pradeshand Nagaland.

Sample Design7

Sample Design - Outline

A stratified multi-stage design will beadopted for the 72nd round survey.

First Stage Units (FSU) –

2011 Census list of villages in the rural sector

Urban Frame Survey (UFS) blocks (UFS2007-12 Phase) in the urban sector

In case of large FSUs, hamlet-groups (hg’s) inrural areas and sub-blocks (sb’s) in urbanareas will form the intermediate stage units.

The ultimate stage units (USU) will behouseholds in both the sectors.

Sample Design8

Total sample size (FSUs)

14088 FSUs are allocated for central sampleat all-India level.

◦ 8016 for Rural Sector

◦ 6072 for Urban Sector

Sample Design9

Allocation – central sample

Allocation of total sample to States/UTs:Proportional to State/UT population as perCensus 2011.

A minimum of 16 FSUs (minimum 8 each forrural and urban sectors separately) will beallocated to each State/ UT.

State/ UT level sample size is to be allocatedbetween two sectors in proportion topopulation as per Census 2011 with doubleweightage to urban sector.

Sample Design10

Stratification

Within each district of a State/UT, two basicstrata will be formed:

◦ (i) rural stratum comprising all rural areas ofthe district and

◦ (ii) urban stratum comprising all the urbanareas of the district.

Sample Design11

Sub-stratification - Rural

If ‘r’ be the sample size allocated for a ruralstratum, the number of sub-strata formed willbe ‘r/4’.

The villages within a district as per frame willbe first arranged in ascending order ofpopulation.

Then sub-strata 1 to ‘r/4’ will be demarcated insuch a way that each sub-stratum will comprisea group of villages of the arranged frame andhave more or less equal population.

Sample Design12

Sub-stratification - Urban

Let, ‘u’ be the sample size allocated for an urbanstratum

‘u/4’ sub-strata will be formed within each stratum

UFS blocks identified as ‘Affluent Area’ within thestratum is made separate sub-strata

Sample Design13

Sub-stratification – Urban (contd.)

if there is no ‘Affluent Area’ block in the stratum, allthe UFS blocks will be divided into ‘u/4’ sub-strata

if only one sub-stratum is formed with the ‘AffluentArea’ blocks, then all the remaining non-affluentblocks will be divided into ‘(u-4)/4’ sub-strata

if two sub-strata are formed with the ‘Affluent Area’blocks, then all the remaining non-affluent blockswill be divided into ‘(u-8)/4’ sub-strata

Sample Design14

Sub-stratification – Urban (contd.)

All the UFS blocks within the stratum will be firstarranged in ascending order of total number ofhouseholds in the UFS Blocks as per UFS phase2007-12

Sub-strata will be demarcated in such a way that eachsub-stratum will have more or less equal number ofhouseholds

The above procedure will be followed separately for‘affluent’ and ‘non-affluent’ part of the stratum

Sample Design15

Allocation to strata and sub-strata

Allocations at stratum level will be adjusted tomultiples of 4 with a minimum sample size of 4.

For both rural and urban stratum, allocationwill be 4 for each sub-stratum.

Sample Design16

Selection of FSUs

Rural sector - Probability Proportional to SizeWith Replacement (PPSWR), size being thepopulation of the villages as per Census 2011.

Urban sector - Probability Proportional to SizeWith Replacement (PPSWR), size being the numberof households of the UFS blocks as per UFS phase2007-12.

Equal number of samples will be allocated amongthe four sub rounds.

Sample Design17

Usual criterion for hamlet-group/ sub-block formation

Selected FSUs with approximate population1200 or more will be divided into a suitablenumber of ‘hamlet-groups’ in the rural sectorand ‘sub-blocks’ in the urban sector with moreor less equal population.

Sample Design18

Usual criterion for hamlet-group/ sub-block formation

approximate present population of the sample FSU

no. of hg’s/sb’s to be formed

less than 1200 1

1200 - 1799 3

1800 - 2399 4

2400 - 2999 5

3000 - 3599 6

…..and so on -

Sample Design19

For rural areas of Himachal Pradesh, Sikkim, Andaman &Nicobar Islands, Uttarakhand (except four districtsDehradun, Nainital, Hardwar and Udham Singh Nagar),Poonch, Rajouri, Udhampur, Reasi, Doda, Kistwar,Ramban, Leh (Ladakh), Kargil districts of Jammu andKashmir and Idukki district of Kerala

approximate present population of the sample FSU

no. of hg’s to be formed

less than 600 1

600 - 899 3

900 - 1199 4

1200 - 1499 5

1500 - 1799 6

…..and so on -

Sample Design20

Selection of hamlet-groups/ sub-blocks

Formation of hg/sb: By equalizing populationmaintaining geographical contiguity.

Two hg’s/ sb’s will be selected:

• The hg/sb with the largest percentage share ofpopulation will always be selected and termedhg/sb 1;

• one more hg/sb will be selected from theremaining hg’s/sb’s by Simple Random Sampling(SRS) and termed hg/sb 2.

Listing and selection of the households will be doneindependently in the two selected hamlet-groups/sub-blocks.

Sample Design21

Selection of households

From each selected FSU and hg/sb, the

sample households for each of the scheduleswill be selected by SRSWOR.

Sample Design22

Sample Design23