Investors can use ROA to find stock opportunities because the ROA shows how efficient a company is at using its assets to generate profits. A ROA that rises over time indicates the company is doing well at increasing its profits with each investment dollar it spends. A falling ROA indicates the company might have over-invested in assets that have failed to produce revenue growth, a sign the company may be in some trouble. ROA can also be used to make apples-to-apples comparisons across companies in the same sector or industry.