<prompt> Human: Im an investing noob but I have already started investing in active mutual funds but was thinking of selling them and moving to index funds but after looking at my returns on an hypothetical 10k Im second guessing myself.___Check out these comparisons...EDIT: I mistakenly was comparing 2 different dates vs. vs. ___Looking at the 10k growth over 10 years:Hennessy Mid-Cap Growth made it to 36k vs. Vanguard Mid-Cap Growth Index 14.5kColombia Acorn Foreign SmallMid Growth made it to 41k vs. Vanguard Foreign SmallMid Growth Index 18k___Why would i sell my active mutual funds go to to an index? Even if the fees are higher so are the returns - by a lot!This is confusing the crap out of me. Can anyone shed some light on this for me?EDIT 2:heres another comparison of two more funds I own, again i just picked these cause of good track records:Large Growth Active Mutual Fund: vs. Large Growth Index Fund: Aggressive: vs Aggressive Index:  <response>: You arent using the same timescales for your comparisons. Hennessy Mid-Cap Growth made it to 36k since February 2003 vs. Vanguard Mid-Cap Growth Index 14.5k since August 2006and Colombia Acorn Foreign SmallMid Growth made it to 41k since February 2003 vs. Vanguard Foreign SmallMid Growth Index 18k since April 2009Of course the returns are wildly different, the comparisons arent even the same...but again, even if a fund did outperform in the past: Past performance is not an indicator of future results. A fund that did great before has an equal or greater chance of doing badly in the future compared to a similar index fund. 