This is great info. Especially thankful to "damjam" for referencing these articles.
As a normal guy who's spent most of his career doing regular payroll contributions to the 401(k), that dollar cost averaging approach is all that I am used to (since it was my only option; there were no lump sums
But for the lump sum approach, it's very interesting to see that about 66-70% of the time you'll be ahead with the lump sum approach.
What I found even more fascinating in the cbsnews article is that the market was up 70% of the time whether you looked a large period from 1926 through 2010 or from during the 10-year period 2001-2010.
To "Sidney" -- who asked about my target allocation -- in addition to rolling over from privately managed funds in my 401(k), my big project now is adjusting to how paying off the mortgage impacts the overall investment strategy. My recent research has confirmed my hunches that paying off the mortgage should be treated like investing in very safe bonds. You would either treat the bond rate as the mortgage percent (if you take the standard deduction) or discount the rates by your marginal tax bracket (if you itemize). With mortgage rates down so much, I am well ahead even for the next few years where I can still itemize. (My mortgage is 3.68% and 10 year T-Bills are less than 2%, and there's no way that I am am even close to an 84% ((3.68% - 2%) / 2%) tax bracket.) Then, when I take the standard deduction in a few years, I'll be even further ahead in paying off the mortgage. Based on this analysis, I am currently over-allocated in bond funds, so when I roll over the 401(k), I'll go heavier (or maybe totally) into stock funds. (I am also balancing with my wife's plan, which is allocated to stocks and bond funds.)