What does 'the more you know going in' mean in the following?

Psychologists led by Baruch Fischhoff of Carnegie Mellon University have documented a disturbing fact: becoming more familiar with
a subject does not significantly reduce people's tendency to exaggerate how much they actually know about it.3 That's why "investing in what you know" can be so dangerous; the more you know going in, the less likely you are to probe a stock for weaknesses. This pernicious form of overconfidence is called "home bias," or the habit of sticking to what is already familiar:

Question

What does 'the more you know going in' mean in the following?

Psychologists led by Baruch Fischhoff of Carnegie Mellon University have documented a disturbing fact: becoming more familiar with
a subject does not significantly reduce people's tendency to exaggerate how much they actually know about it.3 That's why "investing in what you know" can be so dangerous; the more you know going in, the less likely you are to probe a stock for weaknesses. This pernicious form of overconfidence is called "home bias," or the habit of sticking to what is already familiar:

Answer

Here it means what you know about a company before you decide whether to buy the stock.

Answer

Thanks so much!

Answer

Suppose you start to investigate something, like an investment. The phrase imagines it as similar to walking into a building. You usually know _something_ going in. You enter into a learning process and learn more.

Maybe investor X knows very little going in: "Tesla makes electric cars."

Maybe investor Y knows a lot going in: "Tesla's stock has the symbol TSLA. It is run by Elon Musk. It is the biggest electric automaker in the world. The stock has grown a lot. If you had put $1,000 into Tesla stock in 2010, it would be worth $200,000 today."

The study showed that all investors tend to exaggerate how much they know. And that, oddly enough, knowing more doesn't change that tendency. Investors X and Y may be equally overconfident, and equally foolish.