It's no secret that for sports cards, like most collectibles, condition is very important. Cards in top condition sell for more money than those that have some defects, and pristine examples are often the source of great pride for their owners.
In the early days of the hobby, a generally accepted scale of condition was formed using terms that most collectors have heard at one time or another: poor, excellent, mint, etc. While the scale was helpful, it was also subjective, and buyers and sellers did not always agree on the condition of a particular card.
The rise of card grading during the 1990's helped eliminate some of the subjectivity by having impartial parties establish numerical values for the physical condition of cards.
What is Grading?
Quite simply, card grading involves the thorough examination of a sports card by a company with employees specially trained to evaluate the card's condition. After the card is examined, it is assigned a numerical grade and sealed inside a tamper-proof holder (known in the hobby as "slabbing"). Most grading companies specifically state that the grade is invalid if the card is removed from the holder.
While the numerical value is the key part of a card grade, the scale used can vary from company to company. Grades are most commonly assigned using 10-point or 100-point scales, with higher numbers equating to cards in better condition. The old descriptive terms are often still used as well, and though "Mint" once described a card in perfect condition, more recent adjectives like "Gem Mint" or "Pristine" have popped up to signify a card with no flaws.
The grading companies charge a fee for each card they grade. Collectors can often reduce the fee on a per-card basis by having larger numbers of cards graded at once or by allowing more time for the service to grade the cards.
How Are Cards Graded?
Card graders are specially trained to inspect sports cards for flaws or imperfections. They usually wear gloves to avoid doing any damage themselves, and they use powerful lights and magnifying devices to help catch things that might go unnoticed by the naked eye.
The criteria used to establish the grade can vary slightly depending on the service used, but there are three factors that are always important: corners, edges and centering.
Most grading is done on a mail-in basis; collectors mail their cards in to be graded, and the companies mail them back when the process is complete. However, several companies attend sports card shows and will grade cards on-site.
Which Cards Get Graded?
Any card can get professionally graded, and in the early days of the process it was not uncommon to see large numbers of readily available cards graded and offered for sale by home shopping TV stations and the like in the hopes of luring customers. Over time, it became apparent that there wasn't a market for graded versions of every card, and just a few different types of cards make up the bulk of most current submissions.
The most commonly graded cards are those from an athlete's rookie season. These include true rookie cards as well as inserts, parallels and others (such as cards from draft pick sets) that may not fit the RC definition but still have appeal to collectors.
Single cards from older sets are also popular subjects for grading. The scarcity of vintage cards allows them to achieve higher values with lower grades than modern cards, and the holders used by grading companies protect these rare cards from any further deterioration.
Non-rookie autographed cards have seen an increase in grading thanks to the relatively recent development of separate grades for the signatures themselves. Since the consistency of an athlete's signature can vary from card to card, collectors have shown a willingness to pay more to obtain higher quality examples.
Cards with very small print runs usually don't get graded even if they fall into one of the above categories. These cards can be valuable due to their rarity alone, and the money spent to get them graded isn't likely to lead to any perceived increase in value.
Why Are Cards Graded?
Collectors most often have cards graded to ensure higher resale value. Sports cards assigned a top grade by a reputable company can sell for many times more than the same cards in their raw (or non-graded) form.
Many companies also issue population reports that list the exact number of grades they've given for each particular card. For example, a company may have graded 900 Brett Favre Stadium Club rookie cards, but it may have only assigned its top grade to six of those cards. Thus, having cards graded can help establish some rarity even for cards that are otherwise pretty common.
Grading also helps establish authenticity. A helpful side benefit of the grading process is that is can catch and weed out counterfeit cards. That means that a card which is known to inspire a lot of fakes - say, Michael Jordan's Fleer rookie card - may sell at a premium even in less than perfect condition simply because the buyer is assured that it's legitimate.
As mentioned before, protection can also be a motivating factor for having a card graded. While there are many excellent products available to shield sports cards from damage, the holders used by the top grading companies are among the best. Some companies will even slab a card without grading it for a smaller fee.