Quantitative data is anything that is in the form of numbers. This could be in the form of frequencies, for example the number of people who have smoked tobacco compared to the number who have not; or the data could be ordinal, for example how many times people have been to London. Other levels of data are interval and ratio data.
The advantage of using methods involving the collection of qualitative data is that such data is easy to analyse. We can easily compare people in different conditions, and draw reliable conclusions.
A criticism of quantitative methods is that the context in which such data is collected often lacks validity; we over-simplify the research question in order to be able to analyse the data easily and arrive at conclusions.
Techniques involving the use of qualitative data have been developed as a reaction to the ‘number crunching’ approach of traditional experimental psychology. Qualitative data includes such things as transcripts from open-ended interviews, and videotapes from observational studies. This reflects the richness of human behaviour and experience, but is much more difficult to analyse, so we tend not to arrive at such reliable conclusions.
Objectivity and subjectivity
The attempt to make Psychology into a scientific discipline has meant that we have tried to make our investigations as objective as possible, introducing procedures such as double blind trials (where neither the participant nor the person administering the experimental procedure knows what is going on), and focusing on numerical results that can be analysed using statistical methods. Objectivity means carrying out investigations in a way that does not allow for personal interpretation or bias, which may happen unintentionally.
Subjectivity, allowing our personal interpretations to influence research, can be detrimental to the reliability of our results. However, when we use qualitative methods, it is difficult to eliminate such subjectivity.
This is used to analyse the content of data such as that collected from interviews and observations, and generally involves turning qualitative data into quantities, for example by counting up the number of negative and positive statements in an interview. The procedures involved need to be very carefully controlled to ensure that subjective judgements do not creep in. One way to control this is to have more than one person…