Additionally, David Kreinces, founder and portfolio manager of ETF Portfolio Management, argues that the higher return in iShares Cohen & Steers Realty Majors (NYSEArca: ICF) more than makes up for its costlier expense ratio, compared to the cheaper Vanguard REIT ETF (NYSEArca: VNQ).

Commission fees also play a part when an investor evaluates the total cost of owning an ETF. If a portfolio is rebalanced several times a year, commission fees could add up. However, there are a number of brokerage platforms that offer commission-free trades on a number of ETFs. [Six Popular Commission-Free ETF Trading Platforms]

Lastly, investors should take a look at the ETF’s size to infer the sustainability of the investment product. As new products hit the shelves, sponsors may launch ETFs with low expense ratios to compete with existing funds that have gathered a first mover advantage. The low fees may help attract attention, but if the ETF offering falls on deaf years, the fund may be shut down. Over the past few years, ETFs that have been unable to gather enough assets have been axed. [ETF Closures: Not a Cause for Alarm]

For more information on ETFs, visit our ETF 101 category.

Max Chen contributed to this article.