MULTISTAGE SAMPLING
Multistage Sampling
Multistage Sampling is very useful when the population is widespread and it is not possible to list all members of the sampling unit.
It is a complex of Cluster
Sampling.
Cluster Sampling is a
type of sampling that involves dividing the population into groups or
clusters.
Then one or more clusters are
chosen at random and everyone within the chosen cluster is sampled.
Cluster Sampling sometimes
involves selecting samples in two stages but Multistage Sampling involves more
than two stages of selecting the sample.
Sampling involves more than two stages of
selecting the sample. To understand the whole process of Multistage Sampling
Technique, let us take an example
“A Study of Problems in Managing Mid-day Meal by
Principals of Middle Schools of Madhya Pradesh State”
· In
this study the sampling unit is Principals of Middle Schools of Madya Pradesh
State.
· To
select the sample of Principals of Middle Schools, first one should select
Districts.
· Suppose
one decides to select 15 Districts randomly out of 48 Districts.
· From
the selected Districts, one may not be able to take all Principals of Middle
Schools as the number is too large.
o In the first stage Districts are selected
randomly.
o In the second stage, the Middle Schools
from selected Districts are selected randomly.
o
From Principals of selected Middle
Schools, the Principals are selected randomly. This is how the sample of
Principals of Middle Schools is selected in three stages.
o
In Multistage Sampling, after having
selected Principals randomly, one can divide the Sample of Principals as per
their gender, namely males and females.
o In the fourth stage, one can use the Stratified
Random Sampling Technique. Thus, during the process of selecting a sample through
the use of Multistage Sampling, one can also use the Stratified Random Sampling
Technique at the appropriate stage.
Thus, the Multistage Sampling Technique involves selecting a sample randomly in more than two stages.
Types of Multistage Sampling
a. Multistage
cluster sampling
Multistage cluster sampling is a complex type of
cluster sampling. The researcher divides the population into groups at various
stages for better data collection, management, and interpretation. These groups
are called clusters.
For example, a researcher wants to know the different
eating habits in Western Europe. It is practically impossible to collect data
from every household. The researcher will first choose the countries of
interest. From these countries, he/she chooses the regions or states to survey.
And from these regions, he/she further narrows down his research by choosing
specific cities and towns that represent the region. The researcher does not
interview all the residents of the city or town. He/she further chooses
particular respondents from the selected cities to participate in the research.
Here we see that clusters are selected at various stages until the researcher
narrows down to the sample required.
b. Multistage
random sampling
The concept of multistage random sampling technique
is similar to multistage cluster sampling. But in this case, the researcher
chooses the samples randomly at each stage. Here, the researcher does not
create clusters, but he/she narrows down the convenience sample by
applying random sampling.
For example, a researcher
wants to understand pet feeding habits among people living in the USA. For
this, he/she requires a sample size of 200 respondents. The researcher selects
10 states out of 50 at random. Further, he/she randomly picks out 5 districts
per state. From these 50 randomly selected states, he/she then chooses 4
pet-owning households to conduct his research.
Advantages of Multistage Sampling
Technique
1. It is cost effective.
2. It is feasible.
3. It is easy to find sampling unit.
4. It is normally more accurate than Cluster Sampling
of the same size
Disadvantages of Multistage Sampling
Technique
1. It
is not as accurate as the Random Sampling Technique if the sample in of the same size.
2. More
testing is difficult to do.
3. Further analysis is difficult
Applications of Multistage Sampling
- Multistage sampling can be applied to
a multistage design where the population is too large and it
is practically impossible to research every individual.
- Multi-stage sampling can also be used
to conduct surveys on the employees of a multinational corporation
that is in multiple locations in multiple countries of the world.
- Researchers can use multistage
sampling to collect the perceptions of various students on a
particular study even when they are in different locations or
universities and studying different courses.
- Researchers also apply multi-stage
sampling when they have limited time to conduct a study.
Information drawn from the small sample can then be used to draw
inferences on the entire population.
Conclusion
Multistage
sampling is a complex form of cluster sampling, however, it is useful when your
research population is large. It will help you to eliminate the impracticality
of making use of a large sample size. It also limits the risk of bias as the
cluster sample is selected randomly
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