Share your insights or perspective on the financial matter presented in the input.

Should I use put extra money toward paying off my student loans or investing in an index fund?
Yes, it's a risk. To put it in perspective, If we look at the data for S&P returns since 1871, we get a CAGR of 10.72%. But, that comes with a SDev (Standard deviation) of 18.67%. This results in 53 of the 146 years returning less than 4%.  Now if we repeat the exercise over rolling 8 year periods, the CAGR drops to 9.22%, but the SDev drops to 5.74%. This results in just 31 of the 139 periods returning less than 4%. On the flip side, 26 periods had an 8 year return of over 15% CAGR.  From the anti-DS article you linked, I see that you like a good analogy. For me, the returns of the S&P over the long term are like going to Vegas, and finding that after you run the math of their craps (dice rolling game) you find the expected return is 10%. You can still lose on a given roll. But over a series of a larger number of rolls, you're far ahead.  To D Stanley - I agree that returns are not quite normal, but they are not so far off. Of the 139 rolling returns, we'd expect about 68% or 95 results to be 1 SDev away. We get 88 returns +/-1SDev. 2 SDevs? We'd expect only 5% to lie outside this range, and in fact, I only get one result on the low side and 4 on the high side, 5 results vs the 7 total we'd expect. The results are a bit better (more profitable) than the Normal Bell Curve fit would suggest.