1.3 Non-random sampling

Quota sampling

an interviewer or researcher selects a sample that reflects the characteristics of the whole population

Opportunity sampling

taking the sample from people who are available at the time the study is being carried out and who fit the criteria you are looking for

Quota sampling advantages

allows a small sample to still be representative of the population

no sampling frame required

quick, easy and inexpensive

allows for easy comparison between different groups within a population

Quota sampling disadvantages

non random sampling can introduce bias

population must be divided into grups which can be costly or innacurate

increasing scope of study increases number of gorups which adds time and expense

non responses are not recorded as such

Opportunity sampling advantages

easy to carry out

inexpensive

opportunity sampling disadvantages

unlikely to provide a representative sample

highly dependant on individual researcher