Theme 4: Quantitative research - Afterthoughts

I really have to re-think my opinion about this theme’s topic after the lecture and the seminar. The reason for this is that I apparently mixed up subjective and objective estimations with qualitative and quantitative ones. I thought before, that methods like questionnaires which can only collect subjective data of study participants count as qualitative methods. But I was clearly wrong. This is also a quantitative method. So I have to come up with a better definition for myself, what quantitative and qualitative methods are. It can be said that one characteristic of a quantitative method is that it results in numerical measurements. And since a questionnaire leads to numerical data as well as an Electroencephalography both can be categorized as quantitative methods. So this definition is definitely more appropriate than my previous one. In order to make the definition a bit more scientific, it can be added that it is most likely that in quantitative methods an independent variable is manipulated in order to observe changes in the dependent variable. This means that there is always a parameter in quantitative methods which we expect to be influenced. But this leads us to one of the difficulties of quantitative methods: how can it be guaranteed that only the independent variable we wanted to be manipulated gets manipulated and not another one? The real challenge in quantitative methods is therefore to control the manipulation of variables and to be able to exclude other possible reasons for observed changes of the dependent variable. A well designed study should definitely take care of this. However, if the study design provides reliable data it can be evaluated with only low effort. Furthermore, another advantage of quantitative methods is that it can be very easily repeated and verified by other researchers.
In contrast to this, there is no such parameter like the dependent variable in qualitative methods. But what is the result of a qualitative method if not the dependent variable? Well, if we try to gain qualitative data there are very few presumptions or even none presumption at all we can make about it beforehand. Nevertheless, it is sometimes inevitable to use these methods. A good example for this might be a study about the design of an user interface. Besides quantitative usability tests it might be useful to ask participants some open questions like: 'How could this prototype be improved?' It is simply not possibly to cover all potential improvements of an user interface and sometimes researches might not even think about some until a participant mentions it. This is why it is important to use qualitative methods in scientific research as well. Moreover, one might not get a representative result by a questionnaire because they influenced the participants by confronting them with a limited or pre-selected range of answers. Unfortunately, an unlimited possibility of answers also leads to a costlier analysis of the research results.
But in general the best suited methods for a certain study depend on its design and its research field. In natural sciences like physics it is nearly impossible to use qualitative methods whereas in literature studies it is exactly the other way around.