The relative calm of the recovering market means I have had more time to ponder theory surrounding financial mathematics rather than the pragmatic application of theory to real life when a crisis is unfolding.
Having gone through the recent downturn and observed the gains by some investors, it made me wonder whether or not return on investment was the single best measure of performance. Considering that some have taken higher risk than others to achieve comparable returns, I recalled ボーイフレンド had mentioned that the Sharpe Ratio was a good measure of this, so it was time for a bit more technical research.
The Sharpe Ratio is calculated as follows:
Rf is the risk free rate of return, which we can take to be the RBA cash rate (currently 0.25%)
StdDev(rx) is the standard deviation of the portfolio. A guide on calculation can be found here.
The higher the Sharpe Ratio of your portfolio is, the better the returns are at the undertaken risk. As good a tool as it is, the Sharpe Ratio does come with drawbacks, substantively the premise that the lower the volatility, the better the portfolio, it negates the positives of upside volatility. Those who are familiar with the formula are also able to cherry pick performance to demonstrate stable earnings to boost risk adjusted returns as well, so as with most blunt instruments, due consideration needs to be given in application.
In the end, both return and risk need to be considered when evaluating whether or not a portfolio is superior. Just because you took a very high risk and it paid off handsomely doesn't make you a skilled investor so much as it means that you are a lucky gambler (for now).
By 小福
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