So, how do you decide what material to include in the main text of your papers, vs. in appendices?
Some things are easy. Raw data, code, and lengthy derivations belong in appendices.* Alternative ways of running the analysis that lead to the same conclusions belong in an appendix. And these days some journals increasingly only want a summary of your methods in the main text, with the details relegated to appendices.
But what about tougher calls? For instance, you might say that the main text is where you tell the “main” story of the work and present “key” results and analyses, with mere “supporting details” relegated to appendices. I’d say that myself. But if you take that approach to an extreme, it basically says that your main text is your abstract (plus maybe a couple of figures), and everything else is mere supporting detail! I have the impression that Nature and Science papers have kind of gone down this road. I’m old enough to remember a time when Nature and Science papers really were quite different beasts, in both form and content. A good Nature or Science paper told a clear, deep story in a very compact, incisive way. Nowadays, it seems like the main text of many Science and Nature papers is like an extended abstract of an ordinary paper, with the rest of the paper buried in lengthy appendices.
This isn’t just an issue in where to draw the line between main text and appendices. It’s also about which material goes on which side of the line. A result that one person thinks is a mere supporting detail may be viewed by someone else as the most important and interesting result in the paper. Now, you could argue that’s no big deal. After all, the main text and appendices are all there, so anyone who’s more interested in Appendix 27 than in the main text can just read accordingly. But I’m not so sure I buy that. We present our work in narratively-structured chunks–called “papers”–for a reason. As readers, we want and need authors to tell us what to focus on, not to just give us an unstuctured stream of material and say “figure it out for yourselves”. As a reader, I’m trusting you as an author to make a good professional judgement about what the story is. I might not necessarily agree with your judgement, of course, though ordinarily I probably will. I need to trust your judgement because frankly, while in principle I could read all your appendices, in practice hardly anyone (even specialists on the topic of your paper) is ever going to do so.
So, how do you decide what goes in the main text vs. appendices? Have you ever had a decision you struggled with? And does anyone share my sense that the advent of online appendices isn’t just allowing people to report lots of supporting detail that otherwise would’ve gone unreported, but is actually changing how we write our papers in more subtle ways?
p.s. A recent post of Brian’s discussed a case in which he found an appendix of a paper very interesting and important and so wondered why it wasn’t discussed at greater length than the main text. My post was actually in the works before that, so the timing is fortuitous. And that particular case was already discussed in the comment thread on Brian’s post and I don’t want to reopen that discussion. My interest here is in the general issue I’ve raised, not in debating specific examples.
*In ecology, of course–if it’s a math paper the derivation is the paper.