Credit card offers -- can you remember the last time you went a week without getting one in the (junk) mail? Some of these offers for "preapproved credit" are worth looking into, and some should go straight into the bin. But how do you tell the difference between the worst and the best credit card offers?

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Photo source: Flickr user Mighty Travels.

There are a few obvious answers. For example, high annual percentage rates of interest are bad. Low rates are good.

Big annual fee? Bad.

No annual fee? Good.

A 1% "reward" on all purchases, payable in cash or in point? Not bad.

Revolving categories of purchases, for which you must continually sign up to earn rewards? Not good.

The problem
Weeding out the duds in order to find the best credit card offers can take a lot of time. And even when you think you've picked the best option and gotten yourself a spiffy new credit card, there's no guarantee that a new, better offer won't arrive in the mail a few days later. (At which point you cancel one card and apply for the other -- or just keep collecting cards until your wallet explodes.)

There has to be a better way -- and, in fact, there may be a better way.

The solution
We looked into whether there's a pattern to this storm of credit card offers (by one estimate, there are about 1,700 of them available at any given time), and we thought of the following experiment. Making use of Internet Archive's "Wayback Machine," we collated the best-rated credit card offers, as ranked by CreditCards.com, from the past four years, looking for a pattern in which card offers are generally considered "best."

What we discovered is that there's one card-issuing bank that stands head and shoulders above the rest -- one bank you can be reasonably sure won't do you wrong if you take out a credit card from it. We'll tell you who it is in a minute -- but first, the data.

The data
To keep this project manageable, we focused on four major "categories" of credit card, as defined by CreditCards.com:

  • Balance transfer credit cards, which are used to move high-interest debt from one card to a card that charges less interest
  • Cash-back rewards credit cards, which return to you a percentage of the money you spend in cash, rather than airplane travel or hotel stay "points," for example
  • Gas credit cards, which pay particularly large "rewards" on purchases of gasoline
  • Business credit cards,whose benefits are designed to appeal to small-business owners

And because even a tool as all-powerful-sounding as the "Wayback Machine" has only incomplete historical data, we surveyed data from just one month in each year -- specifically, this month: October. So here's what we found out from examining CreditCards.com's top credit card picks for the months of October 2012, October 2013, October 2014, and October 2015.

Balance transfer credit cards
Balance transfer credit cards are perhaps the single part of the credit card market over which banks fight most fiercely. That's to be expected, because offering generous "balance transfer" terms is often the best way a bank can steal customers away from other banks.

Over the course of four years, from 2012 to 2015, three different card issuers were named as having the best credit card offers. Capital One Financial (NYSE:COF) took the top prize in 2012 with its "Platinum Prestige Credit Card" -- which is no longer offered. In 2013, top honors in this category shifted to Discover Financial Services and its "Discover It" card (still available today). Discover held onto the top spot in 2014 as well, but lost it to Bank of America (NYSE:BAC) and its "BankAmericard" this year.

Cash-back rewards credit cards
Competition is a lot less fierce in the category of cash-back rewards credit cards. Here, for three years running, Capital One stood at the top of the heap. In October 2012, CreditCards.com gave Cap1 top marks for its "Cash Rewards" card. That morphed into the "Quicksilver Cash Rewards" card in 2013, and this card dominated the category in 2013 and 2014.

Capital One only stumbled this year, 2015, when Bank of America introduced its "Susan G. Komen" credit card -- a card that, as the name implies, helps to support the Susan G. Komen nonprofit cancer research organization and also offers cardholders 1% cash back on most purchases, 2% on grocery purchases, and 3% on gasoline purchases.

Gas credit cards
Presumably, it was the anti-cancer kicker that helped put the Susan G. Komen card over the top for cash-back credit cards. But it's worth pointing out that Bank of America's "BankAmericard Cash Rewards" card (a Komen-less cash-back card) also won CreditCards.com's endorsement as the best gas credit card in October 2014 and October 2015.

Prior to that, Capital One had owned the category with its "Capital One Cash Rewards" card (see above) in 2012 and its "QuicksilverOne Cash Rewards" card in 2013.

Business credit cards
Our final category -- business credit cards -- presents us with another split decision. In 2012 and 2013, the interminably named "American Express Gold Rewards Card from American Express OPEN" was not only the credit card with the longest name on CreditCards.com's survey, but also the top-rated business credit card available.

In 2014, that advantage shifted to -- you guessed it -- Capital One, which topped CreditCards.com's survey with its "Spark Cash Select for Business" card. Curiously, Capital One managed to win this title despite cutting the amount of cash back paid by the card by a quarter, from 2% (in 2014) down to 1.5% in 2015.

What we have learned
So, what have we learned from all of this research? Across the four years, and four credit card categories surveyed, credit card issuers had the opportunity to be endorsed as having the best credit card offers a total of 16 times. Capital One "capitalized" on this opportunity no fewer than eight separate times.

That's as many wins as Discover, Bank of America, and AmEx racked up -- combined.

And what does it mean to you, the credit card user? In a nutshell, it suggests that for any given type of credit card that you are considering applying for, there are relatively even odds that Capital One will offer you a better deal than any other credit-card-issuing bank out there.

Indeed, taking a snapshot of CreditCards.com's latest survey, for the month of October 2015, it appears that Capital One dominates precisely 50% of the credit card categories being surveyed this year. Capital One has the best credit card offers available for people with "bad credit" and with "fair credit," too. It has the best "business" credit card, the best "no annual fee" credit card, and the best "low interest" card as well. Capital One even has the best cards (in CreditCards.com's opinion) for "no foreign transaction fee," and also the best for "travel & airline" transactions.

All of this suggests that there may be a simple way to decide whether a credit card preapproval you've received in the mail is a "good deal" or not: Simply take the offer you've been given and compare it to what Capital One is offering for a similar type of card. If your offer beats Capital One's, then it's probably a good offer. If not, then look elsewhere.

If you're looking for a bank that consistently has the best credit card offers available, then, as often as not, that bank is the one named "Capital One."

Fool contributor Rich Smith does not own shares of, nor is he short, any company named above. You can find him on our public stock-picking website, Motley Fool CAPS, picking winners (and the occasional loser) under the handle TMFDitty, where he's currently ranked No. 249 out of more than 75,000 rated members.

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