In 2016, Joel Read discussed some important ways science can help people to make decisions. When it comes to making long-term financial decisions, one of the most important factors is the historical returns on a specific investment. The key is to look back at the data in order to determine where the expected returns are, and then make use of that data in deciding what to buy.

You don’t have to make generalizations about how return is trending; there are many different approaches, all with different performance numbers. There is no right or wrong answer, no smooth place to figure out which direction returns are headed next. Generally speaking, the faster you can track the trends, the more valuable you can be as an investor.

At that point, one of the easiest ways to jumpstart your decision making is to purchase an online time series record of the performance of a select investment over a specified period of time. The more accurate you can be in understanding how it’s performing, the more informed you will be. Even relatively small changes can have a significant impact on returns, and these changes are often caused by human action, not mechanical variations in the market.