Objectivity in measurement
Another methodological aspect is the avoidance of bias, which can involve cognitive bias and cultural bias, but also sampling bias. Methods for avoiding or overcoming such bias include random sampling and double-blind trials.
Objectivity in experimental set-up and interpretation
Next to unintentional but possibly systematic error, there is always the possibility of deliberate falsification of scientific results, whether for gain, for fame, or for ideological motives. When such cases of scientific fraud come to light, they usually give rise to an academic scandal, but it is (obviously) not known how much fraud goes undiscovered. However, for results that are considered important, other groups will try to repeat the experiment and fail, bringing these negative results into the scientific debate.
The role of the scientific community
Based on a historical review of the development of certain scientific theories, in his book The Structure of Scientific Revolutions historian Thomas Kuhn raised some philosophical objections to claims of the possibility of scientific understanding being truly objective. In Kuhn's analysis, scientists in different disciplines organise themselves into de facto paradigms, within which scientific research is done, junior scientists are educated, and scientific problems are determined. The implicit social hierarchy of a scientific paradigm ensures that only scientists who are thoroughly immersed in the intellectual construction of the paradigm acquire the reputation and status to pronounce authoritatively on matters of dispute, and those scientists have a vested interest in maintaining the status quo (which confers on them this de facto position of authority).
When observational data arises which appears to contradict or "falsify" a given scientific paradigm, scientists within that paradigm have not, historically, immediately rejected the paradigm in question (as Sir Karl Popper's philosophical theory of falsificationism would have them do) but have gone to considerable lengths to resolve the apparent conflict without rejecting the paradigm, through ad hoc variations to the theory, sympathetic interpretations of the data which allow for assimilation, determination that the "conundrum" the data was obtained to explain in the first place is misconceived, or in extreme cases simply ignoring the data altogether (for example, on the basis of the lack of scientific credentials of its source).
Thus, Kuhn argues, the failure of a scientific revolution is not an objectively measurable, deterministic event, but a far more contingent shift in social order. A paradigm will go into a crisis when a significant portion of the scientists working in the field lose confidence in the paradigm, regardless of their reasons for doing so. The corollary of this observation is that the primacy of a given paradigm is similarly contingent on the social order amongst scientists at the time it gains ascendancy.
Kuhn's theory has been criticised (by Richard Dawkins and Alan Sokal, among others) as presenting a profoundly relativist view of scientific progress. In a postscript to the third edition of his book, Kuhn denied being a relativist.