Quota Sampling

A PRESENTATION ON “ QUOTA SAMPLING ”

Presented By:  (ARYAN’S) AbishekKumar singh Kumar Sharan

Ajit Kumar Gaganjit Praveen Sumanto

SAMPLING üSampling may be defined as the selection of some part of an aggregate or totality on the basis of which a judgement or inference about the aggregate or totality is made. ü üIt is the process of obtaining information about an entire population by examining only a part of it. ü üThe process of selecting sample from the population is called sampling.

WHY SAMPLE ? qSaves money qSaves time qA sample can be more accurate; it has fewer “nonsampling” errors than a census.

TYPES OF SAMPLING

PROBABILITY SAMPLING uSimple random sampling uSystematic random sampling uStratified sampling uCluster sampling uMulti-stage sampling

NON - PROBABILITY SAMPLING

QUOTA SAMPLING

QUOTA SAMPLING

In quota sampling the selection of the sample is made by the interviewer, who has been given quotas to fill from specified sub-groups of the population. For example, an interviewer may be told to sample 50 females between the age of 45 and 60.

CONT …. .

In quota sampling the selection of the sample is non - random. For example interviewers might be tempted to interview those who look most helpful . The problem is that these samples may be biased because not everyone gets a chance of selection . This random element is its greatest weakness and quota versus probability has been a matter of controversy for many years

QUOTA SAMPLING…..

üPre-plan number of subjects in specified categories (e.g. 100 men, 100 women) ü In uncontrolled quota sampling, the subjects chosen for those categories are a convenience sample, selected any way the interviewer chooses ü ü In controlled quota sampling, restrictions are imposed to limit interviewer’s choice ü No call-backs or other features to eliminate convenience factors in sample selection

Quota Sampling Most commonly used non-probability method Select a sample on specified criteria (usually to make similar to target population) Pick people to fill quota on characteristics especially important to research goals Example: Studying political issues, set quota on party identification

Sample of 200 Registered Republicans 50% Republicans 100 Registered Democrats 40% 80 Registered Independents 10% 20

Sampled SampledDemocrats SampledIndependents

Using quotas for several criteria

Race / Ethnicity White Gender

Political F

Latino / a

Gender

Gender

M

Black

F

M

F

Asian Gender

M

M

F

Advantages §Quick and cheap to organise

Disadvantages §Not as representative of the population as a whole as other sampling methods §Because the sample is non-random it is impossible to assess the possible sampling error

Quota Vs Stratified Sampling QUOTA SAMPLING STRATIFIED SAMPLING In Quota Sampling , interviewer selects first available subject who meets criteria : is a convenience sample .

In Stratified Sampling , selection of subject is random . Call - backs are used to get that particular subject

Highly controlled Stratified sampling quota sampling uses without call - backs probability sampling may not , in practice , down to the last be much different block or telephone from quota sampling . exchange

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