Q: What level of evidence is needed for a perspective article?

To begin, your question wasn’t entirely clear. So, we have edited it for greater clarity. Also, by ‘perspective’ article, you may be referring exactly to a perspective piece (which offers a new viewpoint on an existing matter or issue) or you may be referring to a broad category of viewpoint pieces, which are variously called opinion, commentary, reflection, think, and thought leadership pieces. The differences between some of these pieces (and also how to write them) are provided in this article: A young researcher's guide to perspective, commentary, and opinion articles

Viewpoint pieces are usually written by experts in their field, though they could also be written by younger researchers who are zealous about a particular topic. However, they are typically solicited by the editor. In some cases, though, a researcher may pitch a piece to an editor, which the latter may then greenlight if they find the pitch relevant and interesting. In either case, if you are looking to write such a piece, you are possibly avidly interested in a particular topic and are eager to share your informed thoughts and comments on the matter. So, kudos there!

Coming to your query, ‘evidence’ is needed for a viewpoint piece, though its quantum (or level) may vary depending on the nature of the piece or, at times, on the credentials of the writer. It is always helpful, especially in scientific writing, to back your viewpoints with findings, learnings, or viewpoints from previous researchers. This shows the level of knowledge you have of the field (and/or the extent of research you have done in the topic). Additionally, it also shows your ability in assimilating previous information to present a new take on the same topic or issue. You will, of course, need to mention the source for these previous pieces of information in the References section.

Here are a couple of articles from our site as examples. On going through them, you will see that while both are about different topics, they both provide ‘evidence’ to back the statements they are making. You will also see that the amount of ‘evidence’ varies in the two pieces. Additionally, you will see how the structure and flow for both articles are slightly different.

• Is my research significant? Why you shouldn't rely on p values
• Why you should be a skeptical scientist

Coming to the writer credentials, if the writer is a senior researcher, the piece would be more of a thought leadership piece, providing illuminative commentary on a matter of significance. In such a piece, the writer would most probably draw on their experiences (gained over years in the industry), and therefore, such a piece would likely have less ‘evidence.’ The ‘evidence,’ in this case, is meant to be the writer’s rich experience. A piece by a junior researcher, on the other hand, as mentioned earlier, may need a fair amount of referencing in support of their perspective, as junior researchers are still building their experience.

Here are a couple of external articles, one for each such piece just described. In the first, written by a researcher heading a lab, you will find only one linked article. In the second, written by a postdoc, you will find several linked references.

• Mental Health in Academia: What about faculty?
• A Reflection on Current Academia Reality: Is It Gaining Religious Features?

As a final note, you may also go through a few perspective or viewpoint pieces in your target journal to know the kind of pieces they feature and are therefore likely to accept.

Hope that helps. And all the best for your piece!