Should a colleague receive authorship for identifying a research gap and reviewing a manuscript?

Identifying a research gap and reviewing a manuscript does not seem to warrant authorship to me.

Things would be different if your colleague had also worked with you in designing the study, experiment or research project to address the gap she or he identified. Or if your colleague had written part of the manuscript, say the summary of the existing state of the art.

Different disciplines have wildly different conventions on what constitutes enough contribution to warrant authorship. For instance, the American Psychological Association offers resources and a helpful scorecard. At the first link, we find:

An author is considered anyone involved with initial research design, data collection and analysis, manuscript drafting, and final approval. However, the following do not necessarily qualify for authorship: providing funding or resources, mentorship, or contributing research but not helping with the publication itself.

This does not seem to cover your colleague's contribution under the specific conventions in psychology.

I suggest you look over the websites of associations in your field, and/or of relevant journals/conferences, perhaps the venue where you are considering submitting your work. There may be similar resources specific to your field.

Stephan Kolassa's answer is sound general advice.

However, let me add two more points:

• For papers with multiple authors I like a contributions section where each author lists their contributions to the paper. If the contribution sounds embarrassingly small, that's an answer to the authorship question. On the other hand, you may be astonished how much other people did contribute.

  Having the contributions spelled out makes me personally more lenient in the question of co-authorship, because editor and readers then have direct information on the contributions. (In one of our papers, an editor actually reordered the author list because of how important they judged the contributions.)

• For the specific question, both "identified a research gap" and "did a review of the manuscript" can range anywhere from clearly not deserving authorship to major contribution:

  • identify research gap may be "I have a problem. Could anyone please solve it for me?" or it may be "I know this-and-that method from field A and have been looking into how field B uses that other method to do ... Taken together, those two approaches should work for solving our problem C, because ..." which may already be an outline of the idea behind the solution.
  • Internal review can also range from reading and spotting the 3 leftover typos over critically reading and not finding points to improve because the paper is already very good to major work in spotting scientifically weak points and making the paper understandable to the intended audience (I've been internally reviewing a manuscript and in the end became coauthor after spending in total an amount of time on that manuscript comparable to what I need for writing a paper of my own).
    Also, personally I would consider it a similar contribution if someone "just" asks the 5 right critical questions right to the point within a couple of minutes compared to someone spending weeks and tons of emails in groping around the same issues but unable to express themselves clearly.

Science is clearly a collaborative effort, and it is often difficult to claim with absolute certainty the contribution of everyone for a project involving several people.

Furthermore, academic stinginess (even if well meant) in my opinion never moves you and your research field of interest far away, by limiting constructive interactions.

Accordingly, if the identification of the research gap proved momentous and if the manuscript revision consisted in a genuine effort to contribute to the work, then I would definitely think this colleague qualifies as an author.

Whilst journals today have explicit and somewhat crude criteria for authorship, scholarly endeavors should ideally be based on ongoing efforts to maximize participation and inclusion.