This list below shows examples of different types of primary research. It illustrates some of the difficulties associated with obtaining robust quantitative data, for a variety of research subjects. If research follows a scientific methodology then it may be considered science but, as the examples below aim to illustrate, perhaps, not all science is equally robust. This is not due to the researchers; it is because some types of research focus on complex systems, which pose particular difficulties and uncertainties.
The laboratory based aspects of physics and chemistry, followed by biology, represent fairly robust scientific practice. Biology faces the challenge of understanding complex systems, as do some physics spin-off topics - such as weather forecasting and climate modelling. Within each subject below there is, in reality, a range of scientific robustness that is dependent on the nature of the research and the quality of the experimental methodology. Science is referred to frequently in this topic of primary research because it represents a large proportion of modern primary research, and because it represents best practice.
The term "quantitative rating", and its values, are proposals by the author. It does not represent a consensus in the scientific community; and no doubt some may want to argue otherwise (particularly the philosophers).