A vital, fundamental part of all writing is research. Incorrect details can’t yank the reader out of an otherwise good story.
The author has a responsibility to get basic facts correct. Lately, I’ve read a few submissions in one of my writers’ group where easily verifiable details were blatantly incorrect.
It’s the writer’s duty to get the details correct. For instance, it’s incorrect as normal operating procedure to have married Catholic priests, privates giving captains orders, and the sun rising in the west. The internet via search engine searches can explain how each of the above works.
The above examples are easy to verify and get right. Other situations are more difficult. Intricate details on police procedures are far harder to lock down. This is were having a cup of coffee with a law enforcement buddy comes in handy. The same goes for trials. Or academic administration (it’s not a straightforward as you’d assume). Or politics.
A small detail that rings true establishes trust with the reader. Likewise, the detail the reader spots as false will turn him off. Perhaps, he won’t finish the story or finish it, not liking it. Perhaps, it’ll lead to a poor review. And it doesn’t have to.