A steep learning curve every day

Reporters spend their lives on the learning curve. They frequently find themselves investigating a subject they know little about. If it involves complicated material — a public budget, a disease, uranium enrichment — it can be a harrowing experience trying to write a story for the next day's paper. Reporters working on an investigative or enterprise story usually have weeks or months to dig into a subject. That's not enough time to become an expert, but it should be enough time to produce a story that experts would respect. For the most part, there's nothing fancy in getting up to speed on a new subject or a new place. It's a lot of reading and interviewing. The best reporters are humble enough to ask "dumb" questions (two or three times, if need be), smart enough to know what they don't know and brave enough to let go of their first impressions. You are right that there is a danger in getting part of a story and mistaking it for the whole story. The only way to guard against that is to report against the findings of your story, in other words to test your conclusions. The best reporters, when they are finished with an article, understand what people who disagree with their conclusions would say about the subject and make sure that it is reflected in the story. Based on your reference to "ascertainment bias," I assume you are involved in the sciences. I think the reporting process, particularly on an investigative story, is somewhat like scientific inquiry. It begins with a hunch or a tip. Investigation allows you to develop a thesis. And then you have to test your thesis. But what do I know about the scientific process? I'm no expert.