Word nerds will get a kick out of “Checkpoints,” an article by John McPhee in the Feb. 9 & 16 issue of The New Yorker, about the lengths to which his editor, Sara Lippincott, was willing to go in the interests of accuracy. Lippincott, who fact-checked at the The New Yorker for 16 years, cared enough about accuracy that, minutes before press time, she enlisted the aid of the police to track down a source who wasn’t home but who Lippincott was sure could verify a small anecdote in an article about the first large-scale nuclear reactor in the world. Such doggedness is fascinating, if only vicariously, but a friend of mine, who is also a fact-checker, did not enjoy the article as much as I did because she found the author, who likes to “guess at certain names and numbers” and leave the fact-checker to do the detailed research, infuriating.