Not all data is the same. Sociologists sort information by where it comes from and what form it takes, then choose who to study using sampling.
Primary and secondary data
Primary data is information the researcher collects themselves, for example through their own survey or observation. Secondary data already exists and was gathered by someone else, such as government reports, newspapers or diaries.
- Primary data fits the exact question but takes time and money.
- Secondary data is quick to access but may not fit the question perfectly.
Quantitative and qualitative data
Quantitative data is in numbers — for example, 60% of pupils walk to school. It is easy to compare and put in tables. Qualitative data is in words — for example, a pupil describing why they enjoy walking. It gives depth and meaning.
Official statistics
Governments collect official statistics, such as figures on population, crime and health. These are cheap to use and cover huge numbers of people. However, they may be incomplete or collected in a way that does not match a sociologist's question — for example, not all crime is reported.
Sampling
It is usually impossible to study everyone, so researchers pick a sample — a smaller group taken from the whole population they are interested in. Common methods include:
- Random sampling: everyone has an equal chance of being chosen, like names from a hat.
- Systematic sampling: choosing every nth person, such as every 10th name on a list.
- Stratified sampling: dividing the population into groups (for example by age) and sampling from each in fair proportion.
A good sample is representative, meaning it reflects the wider population, so findings can be applied more widely.