Nothing

You may realize the method I described yesterday was roughly what I did for assessing my own performance of investigation: first, compare to a benchmark index; next, compare to doing nothing.

But, if you come to think of it, my suggestion is only good for reviewing the performance (or, in the jargon of extra-terrestrials, for auditing). It could never be used for prospective decision on what to do.

In other words, with this approach, you can occasionally prove what you did was entirely useless or had even led to a worse investment return, but there is no situation where you could justify doing nothing - because, with hindsight, there are always better ways of investing.

Bearing that in mind, you may come to realize it needs both exceptional wisdom and extraordinary self confidence to accept the portfolio at hand is satisfactory and decide one should sit and do nothing.