Perhaps the most dominant trend in the mutual fund industry over the past several years has been the rise of passively managed, index-tracking mutual funds and exchange traded funds (ETFs), which have supplanted a large portion of actively managed assets under management.
As we observe events in realms such as financial markets, politics, or weather, we tend to form beliefs — be they explicit or implicit beliefs — about cause and effect, or whether the events were positive or negative, good or bad. Science has formalized this process: testing a hypothesis with empirical data. One of the tradeoffs when evaluating beliefs in light of evidence, or a hypothesis in light of data, is the type of error we would prefer if our beliefs turn out to be wrong. In the investment realm, this bias can affect our beliefs and behaviors, such as our tolerance for risk and our allocation choices. Several examples will help illustrate this point.