We want to address here a very specific issue: promissory notes.
A promissory note in a manuscript is a statement that indicates that you or your lab will complete a specific research task in future work. Promissory notes are acceptable is a small minority of fields, viewed negatively or discouraged in others, or outright banned by some journals. The problem with promissory notes is two-fold:
- Explicitly stating that your lab will complete the next work goes against the ethos of the scientific community. It does not matter who completes the work—a local high school student has the right to complete it if they are able—and trying to “claim” a future research idea is unacceptable. While getting scooped is a real concern, no scientist can claim an idea prior to completing it.
- Promissory notes are often used to justify incomplete work. The validity of current work should not depend on promises of future confirmation studies; future directions are given for novel contributions rather than required validation of the current results. Promissory notes appear extremely weak and transparent when they are used to ward off potential reviewer criticisms. Do not take this approach under any circumstances.
This is not to say that you cannot use promissory notes. However, when looking to publish you need to be aware of 1) whether they are accepted at your target journal, 2) their broader acceptance in your field of study, and 3) whether you are using them to indicate future directions or to convince a reviewer to accept incomplete work.