View source for Challenge difficulty

For every [[Challenge checker]] in the system there is a ''Challenge difficulty'' calculated. The difficulty is based on on how many [[Geocacher]]s fulfill the challenge or not. Project-GC is running [[Challenge checker]]s in the background for tenths of thousands of [[Geocacher]]s in the background, this process is a part of the [[Auto-Challenge-Checker System]]. The result of these runs is used to calculate the ''Challenge difficulty''.

Basically the *Challenge difficulty* tells us how big share of the [[Geocacher]]s fulfill a challenge or not. The rating is an integer between 0 and 100, but should not be confused with percent. First off it's important to understand that the automatic challenge checker runs aren't automatically executed on the average [[Geocacher]], but more likely on the more hardcore [[Geocacher]]s. It's primarily executed on [[Geocacher]]s with more finds, regular users of [[Project-GC]] and also [[Paid membership|paid members]] of the site.

Then the [[Geocacher]]s the checker has been run on is divided into three categories:
* Region - [[Geocacher]]s that are determined to live in the same '''region''' as the [[Challenge]] itself.
* Country - [[Geocacher]]s that are determined to live in the same '''country''' as the [[Challenge]] itself, but not in the same region.
* World - All others

For each category a percent of how many fulfills the [[Challenge]] is calculated. Then the results for each group is weighted different in the calculations, basically a list is created and the percentages are added into that list. The percentage of *world geocachers* are added into the list 3 times, country 5 times, and region 10 times.

It should also be noted that there usually are more cached checker runs in the system from more local [[Geocacher]]s than from those living far away.

An example:
* The Challenge is placed in Texas, United States.
* 80% of the [[Geocacher]]s in Texas fulfills it.
* 40% of the [[Geocacher]]s in the other states of the United States fulfills it.
* 30% of the [[Geocacher]]s in the rest of the world fulfills it.
* A list containing these values are created: 30,30,30,30,30,30,30,30,30,30, 40,40,40,40,40, 80,80,80
* The ''Challenge difficulty'' ends up being 740/18 = 41.11, which is rounded down to 41. The values are always rounded down to the closest integer.