They’re one of those weak links in the quality control chain; up there with the spine copy and author’s name. Everyone skips over these elements; so systematically checking captions along with those others is an excellent way to earn your keep as the copy editor or proofreader.
The caption for the photo above says they are mackerel, but are they?
The Editors’ Association of Canada’s Professional Editorial Standards place caption checking clearly in the domain of every stage of editing: substantive (B8), copy editing (D9 and D13), and proofreading (E8).
Checklists are an excellent quality control tool, as you already know. Craig Silverman of Regret the Error made a handy checklist for journalists to check their own copy. Combined with your usual spelling and grammar checks, plus the advice in The Canadian Press Stylebook, and we get this:
☐ Confirm spelling of name(s) against the story and against another source
☐ Confirm spelling of place name(s)
☐ Is place named what is shown in the photo?
☐ Count the names and the faces, do they match?
☐ Check order of names: left to right
☐ Confirm positions of people such as “second from right”
☐ Confirm dates and ages
☐ Confirm or omit gender attribution
☐ Confirm action in caption is actually shown
☐ Eliminate misplaced and dangling modifiers resulting from shortening captions
☐ Check for libel
☐ Click links
☐ Call phone numbers
☐ Confirm any numbers match story
☐ Recalculate math
☐ Check figure numbers are sequential
☐ Check font size, type, and style
What else do you check when editing captions? Leave your tips in the comments below.