The CURIOUS Scale is the first rarity/availability scale dedicated solely to computer games. It was started in February 2004 by GOTCHA. This page serves as an explanation of the scale. Anyone may use, reprint or distribute this scale as long as this entire explanation is clearly provided along with a link back to the GOTCHA website. To see an example rarity guide using the CURIOUS Scale, see GOTCHA's CURIOUS Guide. Other rarity guides may be found elsewhere.

CURIOUS is an acronym standing for:

Common Uncommon Rare Imaginary Oddity United States

More detail on the meaning of each word will be presented below. First, some background:

The main purpose of the CURIOUS Scale is to describe the rarity of computer games. It is not meant to imply value to any particular computer game. Although rarer games often are more valuable than common games, this is not always the case. A game may be rare because it was poorly produced and never sold. It may not sell today either. In this case, the game may be rare but worthless. Please do not associate value with rarity when using the CURIOUS Scale.

For the sake of simplicity, the CURIOUS Scale can be referred to as a rarity scale. However, in reality it is an "availability" scale. Its goal is to estimate how common a game is on the open market for trade or sale. For example, a game collector can rest assured that a "Common" game will be readily available, an "Uncommon" game will be harder to find, and a "Rare" game will be very hard to find, let alone purchase. Availability and rarity are very similar, but there is a slight distinction. A game might not be rare in theory (it is known that there is a warehouse full of a particular game), but availability might be low (the warehouse isn't open to the public and the game is hard to find elsewhere). The CURIOUS Scale is technically an availability scale since a game's "rarity" will be judged on how often it shows up on the open market. However, the terms rarity and availability will be used interchangeably for simplicity. Keep in mind that a game's availability may change over time (and thus its CURIOUS rating) based on market conditions. A game's supply may dry up or that hypothetical warehouse may decide to sell off its contents.

Two factors should be used to judge a game's availability -- 1) Expertise and 2) Data from the marketplace. Computer game collectors with years of experience will often judge a game's availability, and that is as it should be. However, raw data is also useful for determining availability. Programs that mine data from on-line auction houses and trading sites can provide hard facts about how often a game shows up on the open market. Although, this data should still be tempered with personal expertise since there is always a margin of error (positive or negative) in an automated system. GOTCHA is currently looking to devise a data mining system of its own. If you wish to help in this endeavor, please contact GOTCHA.

The CURIOUS Scale:

When tabulating a game's availability versus the numbers given below, take into account only condition levels G and above. For an explanation of conditions click here. Usually, a game in worse condition (i.e. G/G ) will be more readily available than the same game in better condition (i.e. MS), but the CURIOUS Scale does not differentiate rarity by condition. Although each category requires that only complete or near-complete (MMC) games be counted.

C = Common -- The most readily available category of games. In any given year, there should be more than 100 complete copies of this game available on the open market in the USA. As a rule of thumb, this will be the most widely used category for games produced after 1994 due to the increased size of production runs and the convergence of PC Gaming onto Intel-based systems. However, Common games can come from any year.

U = Uncommon -- In any given year, there should be 26 - 100 complete copies of this game available on the open market in the USA. As a rule of thumb, for Golden Age Computer games (1979 - 1992), this is the most widely used category. However, Uncommon games can come from any year.

R = Rare -- In any given year, there should be 5 - 25 complete copies of this game available on the open market in the USA. As a rule of thumb, this is the most widely used category for the earliest of computer games (1977 - 81). However, Rare games can come from any year.

I = Imaginary -- This category is used for a game only rumored to exist, but with no known copy in existence in the world. This is meant to act as a confirmation for vaporware or as a placeholder for a game that simply hasn't surfaced yet. For example, a rarity guide can list a game because somebody remembers seeing it in the store in 1982. However, until a contemporary copy surfaces, it should be labeled Imaginary.

O = Oddity -- In any given year, there should be less than 5 complete copies of this game available on the open market. This is the most obscure category in the CURIOUS Scale. For that reason, some people may refer to O as "obscure," but the term oddity is used to also include manufacturing defects and truly odd box or label variations. Oddity should be used sparingly. It is applied to truly limited distribution games such as the original plastic-baggie version of Akalabeth, or a gold master disk, or a singular game with a unique box variation. It does not apply to a game like Star Raiders, which had a box/label variation called "Star Raider." There were so many of these that neither version is rarer than the other.

US = United States -- United States is designated as part of the CURIOUS Scale in order to avoid discrepancies based upon geography. There are two issues: 1) Some games are produced only in specific regions. Therefore a PAL version and a NTSC version of the same game (and associated publisher/box/and label variations) would vary based on geography. 2) The contemporary "open market" is not always world-wide. For example, a US guide could list a game as Rare while a German guide lists it as Common. Both guides could be accurate because the game is available every week on eBay Germany, but the seller does not ship to the USA. Therefore the CURIOUS Scale and associated guides will be based on availability of games in the United States. However, a game's rating may also apply in other countries as well.

GOTCHA realizes that this may alienate collectors outside of the United States. Regardless, all are welcome to participate and use the CURIOUS Scale. Also, GOTCHA whole-heartedly expects there to be foreign partners and competition. There will likely be a CURIOE Scale in Europe and a CURIOA Scale in Asia. GOTCHA has survived for many years based solely on the strength of its acronym. We expect the CURIOUS Scale to do the same. So foreign competitors pose no real threat; although, we are worried about the scale from Southern Italy (CURIOSITY). Considering the southern-Italian computer games market, this is not a near-term problem, and they will be dealt with when necessary.

99% of all games will fall into the C, U or R categories. Only a select few will warrant I or O ratings. A great example of the later is Ultima: Escape from Mt. Drash. Drash was at one time (circa 1998) only a rumor to the staff at GOTCHA. It was seen in a 1983 Compute magazine ad; however, no copies were known to exist. This gave it an Imaginary rating. However, there are now a handful of known copies in existence (although a very few nearly-complete versions). This gives it an Oddity rating. In the future, if more copies surface, it could slip to a Rare rating.

Please address any questions regarding the CURIOUS Scale to Hugh Falk. The most recent version of the CURIOUS Scale can always be found at GOTCHA.


CURIOUS Scale text copyright © 1998 - 2017, Hugh Falk / GOTCHA.