sampling methods

volunteer sampling

participants actively put themselves forward to take part in the study, happens in response to adverts or social media requests

strength of volunteer sampling

sconvenient and easy, committed to study so improves quality as less likely to drop out motivated

weakness of volunteer sampling

bias as they are self selected

participants may share characteristics eg being confident making sample unrepresentative

volunteers often eager to please which may mean demand characteristics

random sampling

reasearcher compiles complete list of all in target population, participants then picked randomly eg out of a hat so therefore everyone has a equal chance.

strength of random sampling

eliminates researcher bias as has no control over who is selected

should be representative so can be generalised to target population

weakness of random sampling

time consuming especially when the population is large,

not guaranteed to be representative as chance may make one type of person heavily picked.

opportunity sampling

reasearcher selects participant who are readily available at the time of the study

strength of opportunity sampling

quick easy and cost effective as easy to find participants, minimal effort and partial when resources are limited

weakness of oppuritnity sampling

highly unrepresentative sample as only includes people who are available

unconsious bias towards certain type of people so hard to generalise the finding

systematic sampling

creating a complete lost of the target population and then picking every Nth (eg 5)

strength of systematic sampling

quick and easy and representative as clear systems to follow

help reduce researcher bias so more representative and easily generalised

weakness of systematic sampling

chance of being a bias sample if by chance there is a pattern on the way the list is ordered

stratified sampling

identify subgroups from within the target population calculates proportion of each subgroup to reflect population, indivuals are then selected from each subgroup usuing a random method

strength of stratified sampling

high representative so the study will be generalisable

has control over categories so selected according to how relevant are in terms or researcher aim

weakness of stratified sampling

very time consuming

WEIRD (hidden bias most study’s contain people in this catogry)

WESTERN

EDUCATED

INDUSTRIALISED

RICH

DEMOCRATIC