The ChallengePoint scoring system is a unique
method of assigning a point value to geocaches
based on a cache's find rate.

ChallengePoint vs. Traditional Scoring System
Objectively Valuing a Cache Based on the Effort Required to Find
The Effort Avoidance Theory in Geocaching
ChallengePoints: Scoring Based on Find Rate
The Math Behind ChallengePoints
Example ChallengePoint Calculations
Other ChallengePoint Notes

ChallengePoint vs. Traditional Scoring System

The traditional scoring system, where one point is given for each cache found, is a straightforward and self-explanatory method of tabulating the cache activity of a geocacher. All cachers know, however, that the amount of effort involved in finding a cache varies widely from one cache to another. In fact, in the time it takes to find one difficult cache, a cacher could possibly have found 30 or more easy ones.

The ChallengePoint scoring system attempts to score caches and cachers using a method that acknowledges such differences. A cacher should expect that for the average person, a cache worth 10 ChallengePoints will require roughly 10 times the effort to find as a cache valued at 1 ChallengePoint.

Objectively Valuing a Cache Based on the Effort Required

While adding up the geocaching.com difficulty or terrain stars for a cache offers some insight into effort required, the result is a highly subjective number. There is considerable variation between one cache owner and another regarding the difficulty rating they apply to their cache. To further subjectify the results, it is likely that the average 5-star difficulty or terrain cache is much more than 5 times harder to find than the average 1-star cache.

The ChallengePoint system uses an immutable law of human nature, which I'll call the Effort Avoidance Theory. It is based on the idea that people generally follow the path of least resistance by avoiding mental and physical effort whenever possible, and can be succinctly stated as:

All other factors being equal, the number of people who will undertake an activity is inversely proportional to the effort required.

By using the premise in this theory, the ChallengePoint system is able to score the effort involved in reaching a cache in an objective way.

The Effort Avoidance Theory in Geocaching

In geocaching, the Effort Avoidance Theory (see above) manifests itself in this way: The less effort required to reach and find a cache, the greater the number of people who will find it in a given period of time. This inverse relationship between a cache's find rate and the amount of effort required to reach it can be evidenced in the following geocaching examples:

Example 1

Two caches were placed on the same street corner in the same week, one year ago today. One cache requires the solving of a challenging puzzle in order to get the coordinates, and the cache container is a cleverly hidden micro. The other cache has the actual coordinates listed on the cache page and is comparatively easy to find. In the past year, the puzzle/micro cache has been found 20 times while the other cache has been found 40 times.

Based on the Effort Avoidance Theory, we know that the 2:1 ratio in the find rate indicates that the puzzle cache requires, on average, twice the overall effort to find as the non-puzzle cache.

Example 2

Two caches are placed in a mountain range at roughly the same time. One is placed in a remote area far from a road, the other is placed near a ranger station along a paved road. Six months later, the remote cache has been found once, while the ranger station cache had been found 5 times.

Based on the Effort Avoidance Theory, we know that the 5:1 ratio in the find rate indicates that the remote cache requires 5 times the effort or challenge to reach as the one on the paved road.

ChallengePoints: Scoring Based on Find Rate

With the ChallengePoint scoring method, each cache is given 100 points per year it exists. A 6-month-old cache would have 50 available ChallengePoints, a 3¼-year-old cache would have 325, etc.

All cachers who have found the cache get an equal share of the available ChallengePoints for that cache. For example, consider a 1-year-old cache, worth 100 ChallengePoints. Assume 20 cachers have found the cache. They each share the available 100 ChallengePoints equally and the cache would be worth 5 ChallengePoints to each finder. If 50 cachers had found the cache, it would be worth 2 ChallengePoints to each finder. If the cache had only been found once, that cacher gets all 100 ChallengePoints.

The Math Behind ChallengePoints

There are two types of ChallengePoint calculations used. The first is the Current ChallengePoint value of a cache. To determine the Current ChallengePoint value, multiply the cache's age (in years) by 100 and then divide by the number of times the cache has been found:

Current ChallengePoints = (100 * cacheAge) / #TimesFound

The second type is the NextFind ChallengePoint value of a cache. This value represents the value of a cache to each finder after the next find. If you found it today, for example, #TimesFound will be one greater than it currently is, and this will affect the ChallengePoints given to each finder:

NextFind ChallengePoints = (100 * cacheAge) / (#TimesFound + 1)

When rating cachers, the Current ChallengePoint score for each cache found is totaled to get the cacher's ChallengePoint score. When comparing caches, the NextFind ChallengePoint score is generally used because it is not mathematically possible (division by zero) to calculate a Current ChallengePoint score for a cache if it has not yet been found.

Example ChallengePoint Calculations

Example 1
Cache Name: Biff's Point Padder #12
Placed: February 1, 2004
Number of Times Found: 50

If today's date is August 1, 2004, then the cache is 6 months old, and the cache age is 0.5 years.

Using the Current ChallengePoints formula,
(100 * 0.5) / 50
the Current ChallengePoints for this cache = 1

Using the NextFind ChallengePoint Formula,
(100 * 0.5) / (50 + 1)
the NextFind ChallengePoints for this cache = 0.98

So for Biff's Point Padder #12, the 50 finders each get 1 challenge point for having found this cache. After the next find, the ChallengePoint value for the 51 finders will be just under 1 at 0.98 each.

Example 2
Cache Name: Sam's Bottom-of-the-Lake Micro Puzzle Cache
Placed: February 1, 2001
Number of Times Found: 3

If today's date is August 1, 2005, then the cache is 4 and a half years old.

Using the Current ChallengePoints formula,
(100 * 4.5) / 3
the Current ChallengePoints for this cache = 150

Using the NextFind ChallengePoint Formula,
(100 * 4.5) / (3 + 1)
the NextFind ChallengePoints for this cache = 112.5

So for Sam's Bottom-of-the-Lake Micro Puzzle Cache, the 3 finders each get 150 challenge point for having found this cache. After the next find (if it were to happen today), the ChallengePoint value for the 4 finders will be just under 113 each.

Other ChallengePoints Notes

Since the ChallengePoint System is based on a cache's find rate, the ChallengePoint score of a cache is dynamic, changing each time it's found and as time elapses. Because of this, the ChallengePoint score of a cacher is also dynamic. A cache worth 10 ChallengePoints when found may be worth 8 or 12 ChallengePoints to that cacher a year later, depending on changes in the cache's find rate.

New caches begin with no ChallengePoints regardless of how much effort is required to find them. A cache's score will usually rise gradually and then stabilize at or near a level that they will keep throughout their life once enough time has elapsed since it was hidden.

Cacher A can affect the ChallengePoint score of Cacher B by finding a cache that has been previously found by Cacher B. The amount of the effect on Cacher B can be determined by subtracting NextFind ChallengePoints from Current ChallengePoints for the cache. This affect, measured by Achilles Points, will be larger if the cache has a very low number of finds.

The ChallengePoint system does not track archived caches. If a cache is archived, the points associated with it are no longer counted in a cacher's ChallengePoint total.