We can know something to be true without being able to point to a dataset, as it’s traditionally understood. We can know, to take just one example, that early silent film relied on the conventions of melodrama to create legible narratives, not because we have a spreadsheet somewhere, but because we’ve immersed ourselves so deeply in our source material that we’re attuned to its nuances.
As one who studied biology on the BSC level we are told we need for any research to be valid at least in data gathered in field research we need at least 1000 case studies in a population and depending on the population for it to be seen as viable.