Non-Probability Sampling Methods

Question 1

• does not involve random selection
• methods are not based on the rationale of probability theory
• not all members of the population have an equal chance of participating in the study

Answer 1

Non-Probability Sampling

Question 2

• selecting elements based on a researcher’s judgement about which elements will facilitate his or her investigation.
• based on characteristics of a population and the objective of this study.

Answer 2

Purposive Sampling

Question 3

• involves describing the target population in terms of what are thought to be relevant criteria and then selecting sample elements to represent the “relevant” subgroups in proportion to their presence in the target population.

Answer 3

Quota Sampling

Question 4

• involves selecting individuals that are readily accessible to the researcher
• include people who are easy to reach
• an easy and inexpensive way to gather data, but there is no way to tell if the sample is representative of the population
• hard to reproduce the results
• can not generalize your results to the larger population
• sometimes called Accidental or Grab sampling

Answer 4

Convenience Sampling

Question 5

• mainly based on ease of access and willingness of individuals.
• people volunteer themselves (e.g. by responding to a public online survey)
• always somewhat biased, as some people will inherently be more likely to volunteer than others

Answer 5

Voluntary Sampling

Question 6

• existing subjects provide referrals to recruit samples
• used for types of research in which the samples have traits that are rare to find.
• also known as Chain-Referral sampling.

Answer 6

Snowball Sampling