Way back in October 2009, I decided to screen for stocks that I thought provided the safest dividends in the S&P 500.

The response to that article was overwhelming, and readers have wanted even more. So I've decided to provide an update -- taking the same 4 rigorous metrics I applied before to discover where the safest dividend in the S&P is today!

Thankfully, the draconian cuts to dividends that we saw in 2008 and 2009 seem to be on the way out. Believe it or not, these cuts added up to $52 billion in lost income to dividend investors -- and those are just the cuts from S&P 500 stocks. To put that figure in perspective, losing $52 billion would put Warren Buffett into bankruptcy.Today, the news looks much brighter. Howard Silverblatt, an S&P analyst, expects dividends to increase +5.6% among S&P companies. Even so, it's clear that dividend safety still has its place. In the first quarter of 2010, only two companies cut their payments -- but those cuts were massive. Valero (NYSE: VLO) cut its payment -67%. Tesoro (NYSE: TSO) completely eliminated its dividend.

To find the safest dividend in the S&P, I'm going to look at the same metrics used successfully to identify our past winners: yield, earnings power, dividend coverage and track record. Let's put these 4 metrics into our stock screener and see what we uncover.

Safety Criteria #1: Yield

When it comes to yield, it usually takes something above 6% to garner even a second look from me. So let's start with all the stocks within the S&P 500 that yield above that magic 6% number.

As I suspected, it turns out the common stocks in the S&P 500 don't offer much in the way of yields overall, but you can still find a few individual companies offering attractive payments.

In total, 13 stocks in the S&P yield 6% or more. Of those, the highest-yielding stock is Frontier Communications (NYSE: FTR), which pays investors 13.4% a year.

With these stocks in focus, I'll now turn to my next metric to uncover the safest dividend in the S&P: earnings power.

Safety Criteria #2: Earnings Power

It's not uncommon for 'sick' stocks to carry high yields. When the outlook is poor, investors will dump the shares, boosting the yield. To combat this potential pitfall, I'm looking at the 1-year growth in operating income (also known as operating earnings) for each of the 13 stocks with a yield above 6%.

Operating income is the profit realized from the company's day-to-day operations, excluding one-time events or special cases. This metric usually gives a better sense of a company's growth than earnings per share, which can be manipulated to show stronger results.

Given the downturn in the economy, I searched for companies on my high-yield list that were able to manage positive growth in operating income during the past year, indicating the business was still able to thrive in one of the worst recessions in recent memory. After screening for positive 1-year growth in operating income, I'm left with the four candidates shown in my table:

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Safety Criteria #3: Dividend Coverage

No measure of dividend safety carries as much weight as the payout ratio. By comparing the amount of operating profit earned against how much is paid in dividends, we can know whether a company can continue paying its current yield, even if conditions worsen.

For some of the payout ratios, I looked at earnings during the past year versus dividends paid. However, there are instances -- such as with REITs -- where depreciation expenses impact earnings, but are actually a non-cash charge and don't impact cash available for distributions. For this reason, I've calculated each ratio by hand, using whatever metrics needed to come to the most accurate ratio.

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Safety Criteria #4: Proven Track Record

Looking into the track records of each of these companies offers good news for investors -- each one has a solid history of paying (and raising) dividends. Depending on what you look for in an investment, I'd consider any one of the four to be the safest dividend in the S&P 500.For example, Altria (NYSE: MO) offers 5-year annual returns of +12.2% and throws off a 6.8% yield. However, it is a manufacturer of cigarettes, which many investors choose to avoid.

Another option, Health Care REIT (NYSE: HCN) has offered annual returns near the +15% range during the past five years and hasn't had a dividend cut since they went public. This REIT invests in healthcare properties, which may be a more palatable alternative to Altria.

The final two stocks I uncovered, CenturyTel (NYSE: CTL) and Progress Energy (NYSE: PGN), operate in two fields loved by income investors -- telecoms and utilities. Both can be counted on to raise payments over the years, although CenturyTel definitely increases payments at a faster pace. In fact, the company just upped its payment +3.5% with the March dividend.

These four stocks are a great place to start for income investors looking for a wide margin of safety. If you have some other metrics that you'd like to test out using a stock screener, check out this educational piece from InvestingAnswers: Stock Screeners -- The Easiest Way to Find Potential Investments.

And if you are an income investor that wants to maximize your cash flow potential, see our article on How to Create a Stream of Lasting Dividend Income.