Primary data

Evaluation

One advantage of primary data is that it is gathered first hand, following careful operationalisation of variables and using carefully chosen procedures. Consideration is given to what is being gathered in terms of data so that they're about 'real life'. Operationalising the IV is done so that it represents what's to be measured. In general, primary data should be valid because the study is designed and carried out for the main purpose of the research. A disadvantage is that it is expensive to obtain because each researcher or research team has to start from the beginning of a study and follow the whole study through, finding participants, organising materials and running the study. Another advantage is that it might be considered to be more trustworthy, in that they have greater validity than secondary data. If they're collected objectively, with careful planning and sampling, controls in place and other features of methodology adhered to, then they're likely to be scientifically gathered for the stated aim of the study. This means they are more credible. Another disadvantage is that it is limited to the time, place and number of participants etc., whereas secondary data can come from different sources to give more range and detail.