The term «quantitative research» is often used by qualitative researchers as a designation of the opposite pole to their own approach. The term is semantically close at hand once the term «qualitative» has been introduced, but I believe this terminology creates problems. First, the specific connotations of quantitative research often remain unclear. In a medical context, this term is often used synonymously with «biomedical», «traditional» or «natural-science» (1) – (3). I therefore tend to interpret «quantitative medical research» as referring to all non-qualitative medical research, meaning all medical research based on the natural sciences.
Quite a number of medical researchers with an orientation towards the natural sciences scarcely feel at home with such a designation. Mathematical or statistical methods are obviously indispensable for a number of natural-science perspectives, but I believe that this use of the term grants excessive importance to mathematics. For example, in a frequently cited article in The Lancet in 2001, Kirsti Malterud wrote: «Numbers alone can never provide the whole range of evidence needed for clinical work...» (1). Today, very few practitioners of natural-science medicine would disagree with this. Most of them recognise that non-quantifiable socio-cultural and psychological aspects play a major role. Quantification is only one of several methods that can be used for exposition of data and standardisation, in the natural sciences as well as in humanities research. A large proportion of basic biomedical research is also undertaken on small samples of material with minimal use of mathematics or statistics, such as studies of microscopic structures, descriptive studies of recently discovered organisms and molecular cell studies with markers that can be analysed visually. Charles Darwin’s research, which led him to the theory of evolution, was also practically devoid of mathematics and statistics, and I am tempted to use the term «qualitative» to describe this work as well.
It often appears as though the randomised controlled study is the objective of the concept «quantitative medical research». Though it ought to be unnecessary, I often feel a need to specify that natural science-based medical research includes far more than just these types of studies. I completely agree that the attention paid to evidence-based medicine has produced an excessive focus on randomised, controlled studies, and even more so on meta-analyses. Much information is lost when the focus is exclusively on large study populations and hard outcomes. This applies to basic biological as well as humanities research. Even in this respect, qualitative researchers have more in common with many natural science-oriented researchers than is the impression from watching the debate.