When siblings contribute to a research paper, do they need to declare their relationship in the competing interest form?

Question

Siblings contributed to a research paper. The publisher asks to fill no competing interest form. Citing the journal in question, it contains the following check box:

☐ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

☐ The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:

What the siblings are obliged to declare? Does "personal relationships" requires them to declare their personal relationship? But what if their relationship certainly does not influence the work? Any suggestions on whether to declare their relationship or not?

Answer 1

There is already an assumption that authors working together have some level of positive relationship - whether colleagues, advisor/advisee, or relatives. These things need not be declared, because they don't influence the content of the work besides all the authors standing by it (which is a minimum requirement for even submitting the paper).

If a sibling has a stake in a company selling widgets and the paper is about how widgets are superior to doodads, then this likely should be reported because the paper could be influenced by a sibling's desire to help their relative's business.

Answer 2

A conflict of interest is when you (the person with the conflict) has an interest in the results that counters or competes, or appears to counter/compete, with the desire to discover the truth.

The fact that the co-authors are siblings, doesn’t in itself, cause a conflict of interest. In fact, I find it rather difficult to come up with a hypothetical scenario where it would lead to a such a conflict. At the most, I suppose that one of them might be participating in order to bolster the other for some reason, but in that case, I would assume that the sibling has an even stronger motive, which should be disclosed or obvious (confirming their own previous research).

A conflict of interest should be understood as a motive sufficient to cause you to endanger your career and reputation by falsifying data. This is frequently monetary, but it doesn’t have to be. But it has to be comprehensibly compelling. This is why companies frequently have a limit on the value of gifts to employees, because it’s not expected that someone would jeopardize a job for a single gift that was of no real value. If you are investigating the effectiveness of a drug, and the CEO of that company once gave you a pack of gum at a trade show, that’s not going to cause you to knowingly make up your results as a way to say thanks. If on the other hand, the same CEO had gotten your child into an experimental trial for the drug, and saved your child’s life, you might, out of gratitude, be willing to exaggerate the effectiveness.

The reason for the rules on disclosing conflicts of interest, are two. One, it gives the opportunity for heightened scrutiny, to find those that have let the conflict override truth. Two, disclosure increases trust, and conversely non-disclosure is superficial evidence of fraud.

If you owe a life-debt to someone or they are your primary source of income and fail to disclose that, upon discovery everyone will assume your results are both fraudulent and useless.