The article shows that how you divide your investments between different types of stocks can greatly affect your returns. By looking at U.S. and international stock portfolios, the researchers found that choosing which economic sectors, sizes, and styles of stocks to invest in can explain a big part of why some portfolios do better than others. In fact, the way you allocate your stocks can explain up to three-quarters of the differences in returns between different funds, and even more than 100% of the overall return level. So, where you put your money matters a lot when it comes to how well your investments perform.