Halfpenny (1984) said that there are two main researcg traditions: interpretivism and postivism. Their views on the aims of researches differ, so they prefer different methods of collecting data.
POSITIVISM looks at the institutions in the society - macro sociology.
Positivists are concerned that sociology is scientific and anakyse social facts. Social facts affect individuals' behavour and can be easily measured. These factors are social external, for example, laws.
They look for what has caused a particular relationship and what are the effects of this relationship.
They favour quantitative data which can be easily turned into numbers and statistics.
They prefer using official statistics, structured interviews and questionnaires with close-ended questions.
INTERPRETIVISM (INTERACTIONISM) looks at the individual in the society - micro sociology.
Interpretivists are looking for meanings and motives behind people's actions like behaviour or interaction with others.
They criticise positivists, because statistics and numbers can't tell much about human's behaviour and that sociology is not a science. The methods that positivists used are also criticised - for example, respodents may not understand a question in a questionnaire or lie.
Interpretivists favour qualitative data - they try to analyse human's behaviour in depth and from the point of view of the individual. That's why they prefer unstructured interviews, where you can ask more about the question you are interested in and ask for details, and participant observation, which helps to understand the behaviour of the studied group by doing the same things and being in their atmosphere all the time.