When data is missing, we overestimate its value. Our mind assumes that since we are expending resource locating information, it must be useful.
We're fascinated with filling information gaps and that obsession can lead us astray. Especially today, when reducing uncertainty has become all too easy.
An interesting study on how our minds work utilizing data. I see this everyday. People are more fascinated with the information they don't know, rather than looking at what is known and making a solid decision based on the facts at hand. So many times a report is issued and there are thirty questions, most of the time the questions are deflecting making a decision. The lack of some piece of data is reason enough to put off the decision and look for further validation.
I believe there is a combination of data and experience hat goes into making a qualified decision. Validation of whether a decision was right or needs to be tweaked happens after the fact. There is never going to be enough perfect data to make a right decision 100% of the time, so trust your experience and the data you have.