In the social sciences (including applied fields, such as my own, management and policy), there are a few kinds of qualitative methods that while in principle could rely on inter-subjective verification, in practice don't really. Among these are biography, phenomenological studies, grounded-theory studies, ethnography, textual analysis, and case studies. There are more kinds, and variations of each. each have their uses in various contexts, but they are not particularly easy to learn how to do, and to make sense of their findings. Many of these kinds of study require a formal assessment of subjective reliability, calling for at least two trained individuals to assess the same information and generally agree with the conclusions based on the premises of the study. Usually, these kinds of studies are preliminary to survey and other kinds of statistical analyses, to identify new potential variables for analysis.
Of course, these methods are not usually appropriate for physics, chemistry, engineering and as on.
edit: Except as analysis of the social aspects of these fields--the sociology of physics, for example, the study of how the people who participate in physics interact as individuals and social units.