SAMPLING
A representative sample is a small group of responses or people that are varied enough to
represent a larger group, such as a population of a country or followers of a specific religion.
This is done to save time, money and effort while conducting research. A clear and correctly
chosen representative sample is crucial to many different types of surveys and studies,
especially large-scale projects. While a sample will not provide the same level of accuracy as
surveying every member of the group, a representative sample is more manageable and
provides data that is easier to process.
Instructions on Choosing a Representative Sample
1. Define the parameters of the testing group. Determine the population you will be
sampling from by listing any demographics or defining characteristics that are important
to the study, such as gender or age.
2. Compile a database of all the individuals that belong to the testing population. The best
method for gathering the names and information of individuals depends on the
population you are targeting. UNICEF recommends including as many people as possible
to get the broadest range of choices for your sample.
3. Split the total study or survey population into smaller categories if necessary. The
Research Methods Knowledge Base recommends this practice for studies that would
benefit from comparing the results of exclusive groups, such as different ethnic groups.
4. Sample from this database:
The following are two examples of probability sampling, through which every individual
in the population has an equal chance of being selected: (a fuller list is in a table below)
o Random Sampling: Select participants from the database, or from each smaller
sub-group, at random. A random number generator, selecting every tenth or
100th participant or other random processes is recommended.
o Stratified sampling: Organize participants into groups and then randomly select a
number of participants proportionally per group.
5. Extract the data from the chosen sample. This could involve sending surveys to the
chosen participants, organizing face-to-face interviews, or any other method of
retrieving the desired information from the representative sample group.

Tips
The larger the representative sample is, the more likely it is to be an accurate portrayal of the
larger population. Information gathered from five members of a million-member group will not
provide a clear result.
SAMPLING

Check your representative sample for unintended bias that could distort the results. This could
include an imbalance in important demographics, like a representative sample of a religious
group that is skewed to sample only older members.
Forms of Sampling (https://explorable.com/population-sampling)
Convenience Sampling
Consecutive Sampling
Non-Probability Sampling:
Quota Sampling
members do not have an equal
chance of being selected (not
Judgmental Sampling
ideal for creating a
representative samle)
Snowball Sampling
Simple Random Sampling
Systematic Sampling
Stratified Sampling
Probability Sampling: every
individual has an equal chance
Cluster Sampling
of being selected
(*Recommended*)
Disproportional Sampling
Sources:
FDC Control, Food Drug & Cosmetic Division ASQC, No. 105, February 1995, p. 4-5, from
http://www.variation.com/techlib/as-5.html
Kolifrath, J. (2010, July 31). How to Choose a Representative Sample. Retrieved May 7, 2015,
from http://www.ehow.com/how_6801699_choose-representative-sample.html
Population Sampling Techniques. (n.d.). Retrieved May 7, 2015, from
https://explorable.com/population-sampling
Representative Samples – Does Sample Size Really Matter? (n.d.). Retrieved May 7, 2015, from
http://www.surveygizmo.com/survey-blog/representative-sample/
SAMPLING
Turner, A. (2003, November 3). Sampling Strategies. Retrieved May 7, 2015, from
http://unstats.un.org/unsd/demographic/meetings/egm/Sampling_1203/docs/no_2.pdf