[Summary]
Hindsight bias is when you look at the results and think you knew it all along.
Hindsight bias makes it easier to see the difference between situations where it is useful and situations where it is difficult to use when it is replaced with actual examples.
In actual investment, the first step is to keep a record of buying and selling and confirm the decision-making process. However, we cannot overlook the fact that self-reflection becomes shallow and it is easy to repeat the same mistakes.
In this article, hindsight bias is not defined as "knowledge" but as a step to check before buying or selling. Don't rush to conclusions, read according to your financial amount and time horizon.
First, distinguish with hindsight bias.
When looking at hindsight bias, first separate what you want to judge. The information you need will change depending on whether you want to know the meaning, confirm before buying or selling, or review your current holdings.
Especially for beginners in investing, the easier the words are, the more they tend to take them as a conclusion. Hindsight bias is not the only factor in making decisions. If you want to check it, it is more realistic to look at it in conjunction with fund management, holding period, and opposing materials.
Thinking about hindsight bias in real life
If we look at hindsight bias as an example, we first make narrow assumptions. It is important not to mix up whether you are talking about the market as a whole, individual stocks, NISA or long-term funds.
Checking the following points will make things a lot easier.
| Axis to check | Seeing with hindsight bias |
|---|---|
| purpose | What do you use to judge? |
| Time axis | Which is closer to short-term trading, long-term holding, or NISA? |
| basis | Which one is more important: price, business performance, interest rates, exchange rates, or psychology? |
| risk | When things go the other way, where should you look again? |
| action | Will it lead to buying, selling, or doing nothing? |
Points that can easily cause trouble in making decisions
Hindsight bias doesn't only trip you up when you lack knowledge. In fact, there are situations where we interpret something conveniently because we know a little bit about it.
- Focus on one situation where hindsight bias works well
- Even if the price movements are similar, if the background is different, they are treated as different things.
- View not only successes but also failures using the same criteria.
- Check if you can reproduce it with your own amount of funds
The important thing here is not to settle on a single correct answer based solely on hindsight bias. In investment, the meaning of the same material changes depending on the market, holding period, and amount of funds. When in doubt, prioritize confirmation over conclusion.
Checklist before buying and selling
Before using hindsight bias as a basis for making an actual decision, check at least these five things.
- Can you explain in one sentence the purpose of looking at hindsight bias?
- Have you confirmed one or more countermeasures or failure conditions?
- Are you investing your living funds or money that will be used soon?
- Have you decided in advance the criteria for cutting losses, taking profits, and continuing to hold stocks?
- Are you making judgments based only on social media or short headlines?
Checklists are simple, but they prevent you from adding reasons after making a decision. The purpose of checking for hindsight bias is not to act faster, but to reduce unnecessary errors in judgment.
Summary
Hindsight bias is a food for organizing investment decisions. Even if you read it as an example, your judgment will be inaccurate if you treat it as a standalone buy/sell signal.
The points to keep in mind are as follows.
- Determine the purpose of looking at hindsight bias first
- Do not mix time axis and amount of funds
- Check not only good materials but also negative materials
- When using NISA and long-term funds, consider how to handle losses
- When in doubt, reduce your position or postpone it.
The more knowledge you have, the safer it seems, but in the market it can become dangerous if you use it incorrectly. It is realistic to treat hindsight bias as a tool to pause before buying or selling, rather than as a word to rush into judgment.