1. You must understand the business of the company.
2. The business must have a durable competitive advantage.
3. The management must have talent and integrity.
4. The price must be reasonable with a margin of safety.
Some may focus just on Filter 4 and still make money in their investing.
However, by incorporating Filters 1, 2 & 3 into their investing, they are less likely to encounter losses.
Filters 1, 2 & 3 are there to prevent losses in your investing.
[Nothing new, I have been following these for umpteen years. My QMV method! ]