Every serious investor has a process. A stack of tabs. A spreadsheet with color-coded tiers. A notes folder organized by sector. A thesis doc that runs twelve hundred words.
The uncomfortable question is whether any of it actually helps you make better decisions — or whether it mostly helps you feel better about the decisions you were already inclined to make.
Here are five research habits that investors treat as rigor but that the evidence, and basic psychology, suggests are doing something else entirely.
1. Reading more sources doesn't improve accuracy — it increases conviction
The conventional fix for being wrong about a company is to do more research. Read the 10-K, then the analyst notes, then the earnings call transcripts, then the bullish write-up on Substack, then the bearish one on Seeking Alpha.
The problem is that most of those sources are downstream of each other. The Substack cites the analyst who read the same filing, quotes the same management team, and applies the same DCF framework everyone uses. Breadth of sources is not the same as independence of sources.
What actually happens when you read more: you feel more informed, which means you become more confident, which means your position sizing goes up. You have not reduced your risk of being wrong. You have increased the cost of being wrong. The extra research is doing real work — just not the work you think.
2. Your investment thesis is a story you constructed, not a conclusion you reached
A well-written thesis is evidence of good writing, not good judgment. The structure is almost always the same: the market misunderstands X, here's the evidence they're ignoring, here's the multiple the business deserves when they figure it out. It reads like a logical chain. It isn't one.
The thesis gets written after you're already interested in the company. You read the bullish case first (usually), you get excited, and then you build the document that justifies the excitement. Each piece of evidence you include is a selection. The contrary evidence tends not to make the cut, or it gets a one-line steelman and disappears.
The thesis is a commitment device, and commitment devices have their uses. But calling it a conclusion is wrong. You started with the conclusion. The thesis is how you talked yourself into it.
3. A decision journal only works if you review it the hard way
Decision journaling is genuinely useful. Writing down why you bought something, what would have to be true to make you sell it, and what would tell you you're wrong — that is good practice. The problem is almost no one does the review honestly.
What most investors actually do: they read back the winners and nod. They skim the losers, find the one unexpected thing that happened (the rate hike, the CEO leaving), call that the cause, and move on. The journal entry that said "this is a high-quality business at a fair price" stays unexamined. You were wrong about the quality or wrong about the price, but the journal has become a monument to your reasoning rather than a test of it.
A decision journal works when you schedule reviews, force-rank your worst calls, and write a post-mortem before you look at whether the trade made money. Almost no one does this.
4. Checking your portfolio daily is not monitoring a position
Price-watching feels like vigilance. You are tracking the market. You are paying attention. You are a serious investor who stays on top of things.
What you are actually doing is activating emotion on a daily basis. The price moves 2% down and your brain registers a threat. It moves 3% up and you feel validated. Neither piece of information tells you anything about whether your original thesis is still intact. The company's competitive position has not changed. The earnings have not been restated. A stock moving 2% on a Tuesday is noise, and you are training yourself to respond to noise as if it is signal.
The investors worth copying — Buffett on Berkshire, a handful of long-only fund managers who consistently outperform — tend to check prices rarely, by design. Daily price-watching is a distraction that feels like diligence.
5. Deep research on one company makes you more susceptible to commitment bias, not less
The more hours you spend on a company, the harder it becomes to walk away. This is not a personality defect. It is how sunk cost operates on human cognition. You have a folder of notes, three earnings calls' worth of transcripts, and a model you've rebuilt twice. Being wrong means all of that was wasted. The brain is very good at finding reasons it wasn't.
The irony is that thoroughness is supposed to protect you from bad decisions, and in some ways it does — you catch more, you know more. But the same work that catches mistakes also raises the cost of admitting them. Deep research and commitment bias are not opposites. They are the same process.
Start here if you want one thing that actually works
Review your worst three decisions from the last two years before you review your best three. Write down what you got wrong specifically — not the external event, but the flaw in your reasoning or evidence. Do this before you look at current positions.
That one practice, done honestly, is worth more than most of the process that surrounds it.