Fast Company interviewed Tom Peters on the twentieth anniversary of In Search of Excellence. In the interview, Peters casually mentioned that he’d faked his data. And neither he nor anyone else thought anything of it!

Smart managers rely on evidence to evaluate the validity of their ideas but as Peters’ remark illustrates, they face a serious disadvantage when compared to the scientific community. To avoid intellectual relativism — a mindset that considers all ideas equally valid — you need trustworthy evidence. Scientists understand this. It’s why articles submitted to scientific journals receive peer review, and no research is fully accepted until confirmed independently. It’s also why discussions among scientists are blunt, sloppy thinking is publicly derided, and anyone caught faking data is expelled from the profession. Scientists require integrity the way professional golfers require good manners.

The sources business people rely on, external and internal, are intrinsically less reliable than the peer-reviewed journals scientists read, and they’re getting worse as intellectual relativism takes increasing hold. Here’s another example:

In the olden days we had access to independent test labs, and trade publications routinely published product performance comparisons. We no longer do, because technology vendors prohibit publication of performance data in their EULAs. This might be so vendors can control what we’re told about their products. It also might be that vendors are concerned that “independent” testing labs and IT research firms have been paid to reach a predefined conclusion.

The concern isn’t unreasonable. Quite a few vendors have complained to me privately about “shakedowns” by well-known IT research firms. Nobody will go on the record — for fear of retaliation, they say, although sour grapes is another possible explanation. The closest I’ve come to direct evidence is a marketing director who happily burbled, off the record, that in exchange for her buying services from one of them, they would “… help us with our marketing efforts.”

The information these firms sell might very well be excellent, but you have no way to evaluate it, or them. The raw data is confidential, their processes are opaque and un-audited, and potential conflicts of interest are significant.

This is what happens when no culture of honest inquiry exists and no process exists to enforce honest research: You lose your ability to trust the evidence. That’s true when it comes to the big IT research firms. It’s equally true when it comes to the sources of information you rely on inside your company.

In small businesses, much of your information comes from direct observation. You know what happened (although even then, interpreting what you see isn’t always straightforward). The bigger the organization, the more you learn indirectly and in summarized form. In very large companies, figuring out what’s actually going on out there is close to impossible.

Many leaders respond by limiting their information sources. They might trust one or two executives in the chain of command. Their administrative assistants might share what’s in the gossip mill. They might rely on a weekly production report that provides “key performance indicators.” But the number of sources is always small, because every additional source of information adds confusion, not clarity. This is so much a way of life for many executives that they miss the thoroughly obvious implication. Which is:

Every additional source of information should improve your understanding, adding depth, color and detail. If that isn’t the case, your organization is guided, not by a culture of honest inquiry, but by the selling of personal agendas. Managers sift through evidence searching for ammunition, instead of letting the evidence tell the story. It’s a hallmark of intellectual relativism — starting with the “right” position on an issue, then accepting and discarding evidence depending on whether it supports that position.

Fixing a culture like this is neither quick nor easy. To start, broaden your range of sources. Meet with a lot of people. Open your door. Convene “user groups.” Invite groups of employees to luncheon roundtables. Start collecting performance measures (yes, metrics are a listening channel — one way of finding out what’s going on out there among many).

Initially, you will become increasingly confused. Stick with it. As you continue to listen to more and more sources a picture will come into focus.

It comes down to this: Some leaders want to find out what’s really going on out there. They want high-quality evidence that tells an accurate, nuanced (if you’ll forgive the over-used word) story. Other leaders start by telling the story and insist you give them evidence that proves them right.

Both get what they ask for.