Answers which are wholly based on "original research" are generally downvoted and may be deleted.
What are the characteristics that (dis-)qualify an answer as original research? How should these issues be corrected?
The general rule for answers is that:
It is up to the answerer to provide valid, verifiable and potentially replicable evidence, and to show convincingly that it is relevant to the question. Every answer should be suitable for review and voting by our community of experts in evaluating evidence. Answers which require non-trivial specialist expertise or are anecdotal in nature are not acceptable due to the nature of this community.
Here is a list of common examples of unacceptable research and how to fix them.
Answers are original research when they perform non-trivial analysis of available data and present a novel result which requires specialist expertise to review. It is acceptable to provide a collection of evidence, but not to apply non-trivial calculations that require a community of experts to evaluate. (This also includes the use of non-trivial Internet-based tools.)
Find a peer-reviewed (or at least authoritative) analysis of such data; don't perform the analysis independently.
Answers are original research when they are based on non-verifiable or non-replicable data, like home-performed experiments.
Provide more reputable data, preferably from peer-reviewed sources.
Answers are original research when they are based on the fact that the answerer found no relevant results when looking at non-verifiable or non-replicable search results, such as Google queries.
When you want to link to a search, typically to "prove a negative":
Use a tool which allows reasonably good replication of the results. For example, Google is known to provide different answers per user, so it's not acceptable.
Use a reputable tool which has an extensive index.
Document your search terms.
Note that you will not be proving a negative so make sure your answer does not jump to unreasonable conclusions. At best, a negative search can support a "probably not" or, more likely, a "unknown" answer.
An alternative approach is to cite a relevant expert in the field, who has reported that they have searched for evidence and found none. This suffers from the Argument from Authority fallacy, and is merely likely to be correct, rather than definitively correct. Despite that, it is sometimes the best we can do to demonstrate a claim has no substance behind it. Once again, care should be taken about the conclusions drawn from such an argument.
Answers are original research if they are based on tools whose validity is unknown or disputed.
If you need to use a tool that is not obviously main-stream, provide reliable evidence that such a tool is reliable and that you are using it as intended.