All fundamental data is wrong in some way. Some of it is incorrect, some of it is published by people with a vested interest, and some of it is lies. I am not angry about it, but I think we should face the sometimes harsh reality provided by the Red Pill.
Let us start with company-provided information. If the history of public corporations tells you anything, it is that anything a corporation tells you should be treated as a lie. Sometimes it is deliberately misleading, sometimes it obscures the truth, and sometimes it just lies to your face. If you do not believe me, then I point you to some of those who were caught: Enron and Lehman Bros stick in the mind, but the list is long.
Do not kid yourself that these are the rogues in an otherwise healthy bunch: every public corporation twists and tortures their information to meet their objectives. In a previous life I was a company auditor, and I can attest that there is plenty of scope for maneuver within the law. In a Barron’s interview, forensic accountant Howard Schilit put it like this:
Here is how the auditors look at the world: They think of themselves and their legal liability issues first; if it’s in the rule book and disclosed, you are covered. Second, they think of their clients. The client asked them to do something, and they want to please the client. A very distant third is they may occasionally ask: How does this look from the perspective of the investor? Investors would be astounded if they realized that this is how the party that is supposed to protect them views the world.
Similarly, the New York Times reported on an investigation by the Public Company Accounting Oversight Board that reviewed multiple audits performed by ten different auditing firms. All of those firms were reported to have performed audits that were unsatisfactory and flawed.
Some data is clearly to be more trusted than others: anything a CEO tells you is not even worth a pinch of salt, whereas tax returns are probably more reliable (not because no-one ever lies on their tax return, but because the consequences of doing so are reasonably high, and there is at least a chance of being prosecuted). But the evidence is overwhelming that company executives have a vested interest in portraying as positive an image of their company as they can, and that they can and do lean on all sorts of levers to manipulate the data they present to you.
Trusting the data a company gives you is like believing what Saudi Arabia tells you about their oil reserves, or what North Korea tells you about their nuclear weapons: it might be in the ballpark of True, but it undeniably comes from someone with a vested interest in the outcome. Company data also carries the material risk of missing information: what they tell you might be true, but what they choose not to tell you is important as well.
It is difficult to believe data released by government organizations either. The US Government and the Federal Reserve have a vested interest in persuading you that unemployment and inflation are lower than they actually are. They might not be deliberately falsifying the figures a la Argentina, but there are more subtle institutional pressures to chose assumptions and methodologies than systematically underestimate certain measures.
Just as pertinent are the revisions. Fundamental data is often revised. Corporations restate their earnings. GDP and employment figures are adjusted materially months later. If data can be revised long after the fact, it makes little sense to base investment decisions on the originally announced variable.
Every computer programmer knows that if you input garbage, you output garage. Doing analysis based on discounted cash flows, or price/earnings multiples or supply/demand components is all well and good, but if you cannot trust the data, you cannot trust the output it produces.
I am not one of the Black Helicopter crowd that sees conspiracies at every turn. I believe that Armstrong walked on the moon, that Oswald shot Kennedy and that earthquakes are generally caused by shifting tectonic plates rather than the CIA*. My skepticism regarding fundamental data does not come from a dark and bitter place, but rather from a frank and honest acknowledgement that data is prepared and released by people and that people tend to act in their own self-interest. Even honest, well-intentioned people are humans, and humans are susceptible to spinning bad news as good and lying by omission.
I use fundamental analysis every day. It can be an important part of the trading process. However, I treat all fundamental data with a strong pinch of cynicism, a healthy sense of skepticism and a highly-refined BS Detector. When placing my own money at risk, I think it is better to see the world as it is, rather than how I might want it to be.
* I think that people are attracted to conspiracy theories because they find comfort and security in the notion that someone is in charge, rather than accepting that most things happen due to random chance.