The study looked at why some mutual funds don't keep performing well over time. They found that how investors and fund managers react to past performance affects future results. Funds that did well in the past but didn't get a lot of new money or change managers did better in the following year. On the other hand, funds that did poorly but changed managers and had a lot of money taken out did better in the next year too. These effects were especially strong for funds that didn't do well before.