Dividend yield is calculated as the dividend paid per share divided by the stock price.
Dividend yield is commonly perceived as the cash return in dividend income you will receive by buying the stock. Dividend investors typically screen for high-dividend yield stocks to build up their dividend portfolios.
Caveats in buying high dividend-yield stocks
That Was Last Year's Dividend, Not This Year
Dividend yield is often calculated using the dividend paid out for the last financial year. Dividend yield can be distorted by special dividends which are repeated this year. Also, for companies which pay out dividends as a fixed percentage of net income, last year's dividend is no indication of this dividend since earnings are unpredictable.
Dividends Aren't High, Prices Are Low!
At times, unfamiliar faces appear in the high dividend-yield screen. It could be a one-time increase in dividend last year or simply that the stock price collapsed, artificially creating the illusion of sustainable high dividend yields. Furthermore, falling share prices typically reflect deteriorating fundamentals and reduced ability to pay dividends, at the very least in the short term.
There is nothing wrong with using high dividend yield as a metric to screen for dividend stocks. However, investors should do their homework on the dividend payouts and not buy a basket of high dividend yield stocks blindly.