1.3 Non-random sampling Flashcards
What are the 2 types of non-random sampling?
» Quota sampling
» Opportunity sampling
What is Quota sampling?
» An interviewer or researcher selects a sample that reflects the characteristics of the whole population
What is the role of the interviewer?
» Meet people, assess their group, allocate them into the appropriate quota
» Continues until quoata is filled
What is opportunity sampling?
» Consists of taking the sample from people who are available at the time the study is carried out and who fit the criteria you are looking for
What are the advantages of Quota sampling?
» Allows a small sample to representative of the population
» No sampling frame required
» Quick and easy and inexpensive
» Allows for easy comparison between different groups within a population
What are the disadvantages of Quota sampling?
» Non-random sampling can introduce bias
» Population must be divided into groups, which can be costly and inaccurate
» Non-responses are not recorded as such
» Increasing scope of study increases the number of groups which adds time and expense
What are the advantages of opportunity sampling?
» Easy to carry out
» Inexpensive
What are the disadvantages of opportunity sampling?
» Unlikely to provide a representative sample
» Highly depended on individual researcher
Describe how quota sampling works
Divide the population into groups according to given characteristics
The size of the each group determines the proportion of the sample
The interviewer assess which group people fall into the study
Once a quota has been filled, no more people in that group are inteviewed
Describe the process of opportunity sampling
Consists of taking the sample from the people who are available at that time of the study
Explain why opportunity sampling is unlikely to be representative?
» Unlikely to reflect the characteristics of the whole population
