One figure at a time, please

(My writing pet peeves, part 3)

When you’re reading a thesis or a paper, have you ever come across a sentence like this one?

“Diet overlap between species increased from 2004 – 2009 in four of six comparisons: ribbon snake – green snake, mud snake – milk snake, milk snake – ribbon snake, and milk snake – green snake (Fig. 2A-F, Figs. 3 – 6, Table 3).”*

I bet you have (unless you’re reading an entirely different literature than I am).  I come across such sentences often, and every time, they make me see red.

Have you ever written a sentence like that?  Then we need to talk.

It’s simple, really.  When you refer to multiple figures and/or tables at once, you ask the reader to do your work for you.  It’s the writer’s job, not the readers, to find and point to the pattern in the data that supports a particular point.  A reader who’s asked to inspect several figures and a table in order to find that pattern is a reader whose patience is being tested.  And, given the size of our literature and the demands on everyone’s time, that’s a reader who’s likely to move on to some other paper.

By the way, it’s bad enough to send the reader to several figures, but it’s even worse if you mix figures and table in a single reference**.  Figures and tables are very different constructs, requiring different kinds of decoding – so you’re asking the reader not just to do a complex task, but to switch between two different complex tasks.  Well, more than that, actually, because every time you refer to a figure (the same goes for a table), you ask the reader to leave the text, navigate to the figure, switch to the different encoding of a figure (vs. text), and then navigate back to pick up the thread.  This is a significant task already, and a good writer tries to make that task easier, not harder.

I’m pretty sure I know where this habit comes from.  The snake sentence betrays that its author came at things from the wrong perspective.  If you write a sentence like that, it’s because you made a bunch of figures and tables that show your data – as opposed to deciding on the story you want to tell your readers, and then constructing figures and tables showing how your data support that story.  It’s a subtle difference, but an important one.  It’s one part of a mental reorientation away from a narrative of what you did and what you found, and towards a deliberate focus on what you want your reader to understand from reading your paper.  The former is the way we’re often encouraged to write in undergraduate laboratories, and it’s a hard habit to break; but the latter is how we write good, clear papers that our colleagues will read without resentment.

So: one figure at a time***.  And while we’re at it: readers will be grateful for more than just a cavalier “Figure 1”.  Try “compare slopes of traces in Figure 1” or “Figure 1; notice greater dispersion in panel A vs. panel B”.

Reading science is hard. Let’s not make it harder than necessary.

© Stephen Heard (sheard@unb.ca) February 9, 2017

More of my writing pet peeves: Statistics and Significant Digits, and Friends Don’t Let Friends Use “cf.”

This post is based in part on material from The Scientist’s Guide to Writing, my guidebook for scientific writers. You can learn more about it here.

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*^This is a real sentence, from a manuscript I once reviewed, except superficially disguised to protect the oh-so-very-guilty.

**^Please don’t read my old papers to see if my own nose is clean on this one.  I won’t like what you find.  I used to be a big fan of “X was significantly higher than Y (Figure 1, Table 1)”, where the figure showed the pattern and the table had the stats.  That’s not a horrible way to present things, but I should have invested a couple of extra words and written “X was higher than Y (Figure 1), and the difference was significant (Table 1)”.  This is one place not to worship at the altar of brevity.

***^And don’t take this as a suggestion to simply build a 19-panel figure.  See pp. 112-113 of The Scientist’s Guide to Writing for my rant about that.