Dividend investing is a tried-and-true strategy for generating strong, steady returns in economies both good and bad. But as corporate America's slew of dividend cuts and suspensions over the past few years has demonstrated, it's not enough simply to buy a high yield. You also need to make sure those payouts are sustainable.

Let's examine how PetMed (Nasdaq: PETS) stacks up in four critical areas to determine whether it's a dividend dynamo or a disaster in the making.

1. Yield
First and foremost, dividend investors like a large yield. But if a yield gets too high, it may reflect investors' doubts about the payout's sustainability. If investors had confidence in the stock, they'd be buying it, driving up the share price and shrinking the yield.

PetMed yields 4.2% -- moderate and worthy of further investigation.

2. Payout ratio
The payout ratio might be the most important metric for judging dividend sustainability. It compares the amount of money a company pays out in dividends to the amount it generates. A ratio that's too high -- say, greater than 80% of earnings -- indicates that the company may be stretching to make payouts it can't afford.

PetMed's payout ratio is a moderate 51%.

3. Balance sheet
The best dividend payers have the financial fortitude to fund growth and respond to whatever the economy and competitors throw at them. The interest coverage ratio indicates whether a company is having trouble meeting its interest payments -- any ratio less than five is a warning sign. Meanwhile, the debt-to-equity ratio is a good measure of a company's total debt burden.

PetMed doesn't carry any debt.

4. Growth
A large dividend is nice; a large growing dividend is even better. To support a growing dividend, we also want to see earnings growth.

Let's examine how PetMed stacks up next to its peers:

Company

5-Year Earnings-per-share growth

PetMed

13%

MWI Veterinary Supply (Nasdaq: MWIV)

26%

VCA Antech (Nasdaq: WOOF)

5%

Vitamin Shoppe (NYSE: VSI)

99%*

Source: Capital IQ, a division of Standard & Poor's.
*One-year growth rate.

Over the past five years, PetMed's earnings have grown fairly nicely, though not at the breakneck pace of MWI.

The Foolish bottom line
PetMed exhibits a fairly clean dividend bill of health. It has a reasonable payout ratio, no debt, and earnings growth.

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Ilan Moscovitz doesn't own shares of any companies mentioned. You can follow him on Twitter @TMFDada. The Motley Fool owns shares of PetMed Express. Motley Fool newsletter services have recommended. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.