Sampling Methods - Research Methods

people who have chosen to take part in the study (also known as self-selecting)

Example: people who respond to an advert for participants

Strenghts:

• relatively convenient and ethical if it leads to informed consent
• reduces researcher bias by not choosing participants

Weaknesses:

• unrepresentative - leads to participant bias (e.g. a daytime TV advert would not attract full time workers)

selecting people available at the time

Example: going up to a person in a cafe and asking them to be interviewed

Strengths:

• Quick and conveneient (most commonly used type)

Weaknesses:

• very unrepresentative samples and often biased by researcher choosig those who appear most helpful

Every member of the target population has an equal chance of being selected

Example - pulling names from a hat

Strengths:

• For very large samples it provides the best chance of an unbiased, representative sample

Weaknesses:

• Not always ensure an unbiased sample is chosen - for example all girls may be randomly pulled from the hat
• Time consuming creating a list of names in a large population

Dividing target population into important subcategories and selecting members in proportion to the way they occur in the subcategories

Example - 60% of the population are females so 60% of the sample are female

Strengths:

• deliberate attempt to make the sample representative

Weaknesses:

• can be time consuming as subcategories and proportions have to be identified

taking every nth person on a list to create a sample

Example - taking every fourth person

Strengths:

• unbiased selection increasing chances of unbiased and representative sample (no researcher bias)

Weaknesses:

• not always representative - may end up selecting all females