Most psychologists would argue that the Quantitative method is the most valuable in psychology as it produces the most reliable results and it is the most scientific. The main advantages of the quantitative method are that, firstly, they can strongly establish cause-effect relationships with reliable results. Also, quantitative methods are standardised across experiments and all scientific disciplines, enabling us to conduct valid meta-analyses. Quantitative methods are also less based on personal interpretation, so one might also say that they offer less bias results. A criticism of the quantitative method is that it offers no explanation for it’s results, an often, they have little meaning. Some might say that human nature is to complex to be analysed in such a straight forward manor, that often uses closed questionnaires and very simple tests, and that psychology research should take a more explorative approach.
Qualitative research attempts to do exactly this. It attempts to describe and understand behaviour, and generate new hypotheses. It therefore provides us with rich meaningful data, and a deep understanding human behaviour and emotions that quantitative data simply cannot offer. However, we can question the reliability and validity of qualitative research; it is often difficult to control all independent variables, for example, in naturalistic observations and case studies. There are also often relatively few participants in qualitative studies, due to the time it takes to code the data, and there may be few participants that fit the necessary criteria, therefore limiting the validity. Also there may be differences in the coding and transcription of qualitative data, although a standardised process is often used, the process may be partially subjective, also jeopardising the validity and reliability of research results.
Possibly, a combination of the two methods might prove to be the most valuable method in psychology. This is possible with a mixed methods design, which may incorporate both qualitative methods and quantitative methods. It may code qualitative research in such a way that we can use statistical methods to derive meaning from it. It may also take it’s form in a questionnaire or interview that comprises both open and closed ended questions. I therefore think that data from a mixed methods design will provide the most meaningful and valuable data. However this is not always possible, and if it were between purely qualitative and purely quantitative data, I would say that qualitative data is more valuable in psychology, as I agree with the statement that human behaviour is too complex to investigate in a quantitative, statistical manner.