Participants

• Target population = Refers to the group of individuals a research is interest in 

  • For this piece of research I am interested in studying people above the ages of 75

  Sampling frame = Refers to the smaller group that is taken from the target population which the researcher is going to sample their participants from

  • For this piece of research I will be gathering individuals from a retirement home

  Sample group = Refers to participants actually used in the research, this is the sample which will be taken from the sampling frame
• Opportunity

  Choosing people who are available at the time, for example people who are walking past the researcher within the street

  + Quicker and easier = more data = better understanding unlike stratified

  + Appropriate where sampling frame is unknown

  x Biased sample due to small section it is drawn from = unrepresentative unlike stratified which selects from across sampling frame

  x Increased chance of researcher bias unlike random where everyone has equal chance
• Self-selected 

  Advertise for participants in a newspaper, on a noticeboard or the internet. Those who want to take part then volunteer from it

  + More ethical as consent is secured

  + Quick and easy way of gaining participants than stratified

  x Prone to volunteer bias since certain individuals may volunteer e.g. extroverts

  x More likely to get demand characteristics as they may be eager to help
• Systematic 

  Using a predetermined system such as every 14th or 20th person to select every nth participant from the target population

  + Less chance of bias due to objective system unlike opportunity where researcher approach participant

  + Quicker sampling technique than stratified 

  x Biased sample due to the chance of a freak representative unlike stratified which selects participants from each strata in proportion to the rate they appear 

  x Not practical when sampling frame in unknown unlike snowball which may be more appropriate 
• Random 

  Get a list of all people in the target population, write the names on a piece of paper and then place it into a hat. Select the number of participants needed from this hat to create the sample group

  + Unbiased as everyone has equal chance of being choses = more representative + generalizable

  + Less chance of researcher bias as the random technique unlike opportunity

  x Time consuming, researcher must identify all target population, then select unlike opportunity

  x Freak unrepresentative sample unlike stratified which selects from each strata in proportion to the rat they appear
• Snowball 

  Find one participant who will be used to then further recruit more participants amongst people that they know, for example, recruiting a drug addict in rehab to recruit further addicts they know

  + Useful at gaining access to difficult to reach participants = most appropriate

  + Appropriate when the sampling frame is unknown

  x Unlikely to be the most representative due to it likely being friends or families = harder to generalise findings to target population

  x More time consuming unlike opportunity as researchers need to wait for participants to come to them
• Stratified 

  Subgroups within target population (e.g. males and females), ppts are then gained from each strata in proportion to the rate they appear in the target population. Selection from the strata is done using random technique 

  + Most representative sampling method as there is proportional representation of subgroups = findings can be generalised

  + Less chance of researcher bias (random technique) unlike opportunity

  x Time consuming as all subgroups have to be identified, then selected at random unlike self selected

  x Likely to have some bias as not all subgroups can be identified 
• Quota 

  Subgroups within a target population are identified (e.g. males and females), ppts are gained from pre-set numbers from each strata. Selection from the strata is done with non-random technique e.g. opportunity

  + Most representative, proportional representation of subgroups therefore findings can be generalised

  + Quicker than using stratified sampling = more data can be gathered

  x Time consuming as all subgroups have to be identified, then selected by opportunity unlike self-selected

  x Researcher bias, non random technique used to select participants