How to prove that enough cachers are fulfilling my new challenge cache?

Question

My reviewer asked me to prove  that my new challenge cache needs to be attainable by a reasonable number of cachers (around 20 in the area). This is refering to the guidline saying

“A challenge cache needs to appeal to and be attainable by a reasonable number of cachers. Your reviewer may ask for a list of cachers from your area who qualify.”

How can I check and prove this?

The challenge is: „Find at least one cache in each of the 28 EU member states“

Answer 1

When I've created challenge caches I've done the hard work manually. Tried to find people in my area with the most finds/most of one type or whatever it is, and then surfed their profile to see if they qualify. If they do, I put the profile name in a reviewer note till I have the amount of people needed in my area - or if many qualify I've put "at least xxx people are qualified according to (pgc-link to a stat-page". I haven't had any trouble with the reviewers doing so - even when I've sent it in and not yet been qualified myself, but promised to be before the release. (I own 27 challenge caches so far).

Comments

Thank you for your help, meanwhile the Cache has been published in Berlin. If you will be in the area, check out GC7Q9AB.

---

Very nice - congrats :-) I have no plans on going to Berlin though - and do absolutely not qualify as I only have 13 countries in total counting a few non-EU countries as well. Love the D/T rating though :-)

Answer 2

I would do it like this:

Start by getting a list of all people with finds in 28 or more countries.
https://project-gc.com/Statistics/TopNumCountries

Then go down the list and see how many have made it. The top guy def. has.

I'm missing 4 :(

Comments

Thank you for your help, meanwhile the Cache has been published in Berlin. If you will be in the area, check out GC7Q9AB.

Answer 3

It really depends what your challenge is. Can you give some details of what finders have to achieve in your challenge as checking may or may not be possible with various tools here depending on your criteria?

Comments

Yes, I just added the challenge task to my question, see above

---

You could use PGC to find the top geocachers in some EU countries (perhaps central ones) then use PGC to examine their profile to look at their EU map. After examining 20 or so you can probably come up with a statement that "any user with xxx finds from these countries is likely to have found caches in 28 EU states, and PGC reports there are over yyy geocachers with at least that many finds"
Also remind the reviewer, that while some challenges are easy and should appeal to a wide range of geocachers, some experienced geocachers also like to be challenged.
And the "area" in this case is the whole of Europe.

---

Thank you, it was a bit of work but finally I found 20 users to fulfill the challenge!