I recently finished listening to a "Poetry Podcast," available at the website for The New Yorker, called "How Do You Fact-Check a Poem?" It features a fact-checker for The New Yorker. I wasn't aware that publications had fact-checkers for poetry.
I do a lot of fact checking whenever I work on a poem. Many of my poems involve geography, and I want to make sure that my geographical references are accurate. Fact checking is important to me, and I want to save myself the embarrassment that would come from getting directions, longitudes and latitudes, weather and seasons, or flora and fauna wrong. For example, in my recent poem "Vintages," I mention that elsewhere, where it is summer, clusters of grapes are growing and await their harvesting. Though I did not expressly declare it in the poem, the speaker is in the Northern Hemisphere where, tonight, the temperature will drop to 20F (-6.6C). However, Argentina is at the height of summer, and the temperature there is currently 99F (37.2C). Yes, grapes are growing right now in the Southern Hemisphere from which the next vintage will yield! I have written other poems where a discrepancy would be even more apparent and it was even more important to me that geographical references made sense. In my poem "Prudhoe Bay," I make reference to the north pole; I refer to it as "ninety degrees north." I had to look into that to make sure that that actually is the coordinate for the north pole, and it is; zero degrees would be the equator. There have been several other instances where it has mattered to me a great deal that my facts, geographical and others, were expressed correctly.
Then there is the matter of artistic license. Sometimes it is possible to get so bogged down with fact that one loses sight of the art and its message. In my poem "Goodbye," I was dealing with what seemed like chronological inconsistency, and I could not decide on past versus present tense in a part of the poem. An esteemed PMO member, @Benjamin, reminded me that, "Yes I think this poem works fine in the present tense with the chronological issues you stated -- 'it is poetry after all' -- and the appreciative reader still requires the courtesy of having a little imaginative work to do ... " I appreciated this help very much, and it comes to mind whenever I start to get overly bogged down with facts while composing a poem.
Do you fact check when writing poetry? To what extent?