I was recently asked how a fiction author avoids bias. The simple answer: she doesn't.
The questioner, who reads political spy thrillers, was irritated with a certain author because the author appeared to have an agenda in some books.
We all know authors write from their own worldviews. We all know authors write about topics that interest them (unless they have a specific reason that they can't, like "need money now so must accept boring freelance work"). Unless the author is a journalist devoted to giving just the facts (and how many journalists are encouraged to do that, nowadays?), bias will be present. I would argue bias is present even for the journalist, based on what facts are presented and in what order.
For the reader, it's not a question of avoiding bias. It's a question of which biases agree with your worldview, or, which biases stretch your worldview. I suspect a reader's favorite authors will demonstrate a close approximation of how the reader views the world, and, contrarywise, his least favorite authors will clash with his worldview in a manner too disconcerting to accept.
For the author, the question could be "will this presentation of the universe as I understand it enthrall or disgust a reader?" Or, in Christian fiction, "will the CBA/ God/ secular worldview" be OK with my story? You know. The old "who's my audience" question.
Biases will present themselves on paper. A variety of good beta readers will help illuminate them. One or two reviews will illustrate them immediately, if you can stomach reading reviews. The best advice I can give to an author who wants to consistently sell her writing is "know your audience," write to their biases and don't worry about the rest of the world.
Happy Monday, dear readers. New week, fresh start. Enjoy.