(from http://www.wrtc2018.de/index.php/en/competition/qualification/selectioncriteria2)
The Event Score for each qualifying event
will be calculated based on the following formula: Event Score = (Contest
value) x (Category weighting factor) x (Published final score / Maximum score
in applicant’s category from Selection Area*)
* If the “Maximum score in applicant’s category from Selection Area” is lower
than the highest published score in any “lower” category from the same
Selection Area, substitute the higher score as the reference score using the
following category order and revised formula below.
Category Order 

1. 
MM 
5. 
SO HP 
2. 
M2 
6. 
SOA LP 
3. 
MS 
7. 
SO LP 
4. 
SOA HP 


Event Score = (Contest value) x (Category weighting factor) x (Published final score / Maximum score in lower category from Selection Area)
Example:
DL1AAA has a published final score of 3,000,000 in CQ WPX CW (Value = 950) as a
M2 entry (Category Weighting Factor = 0.8). The maximum score in M2 in DL1AAA’s
Selection Area (EU #7) is 4,000,000. Up to 3 operators at DL1AAA may submit the
following result from this contest:
950 x 0.8 x (3,000,000 / 4,000,000) = 570.0
If there was a MS (a “lower” category than DL1AAA’s entry category of M2) in EU #7 that had a published score of 5,000,000, then the calculation is:
950 x 0.8 x (3,000,000 / 5,000,000) = 456.0
Event Scores made outside an operator’s home Selection Area are evaluated against the top score in the Selection Area from which the score was made. Example: DL1BBB (EU #7), operating from CT9, receives points from evaluating the score against other scores from AFN/W instead of against scores from EU #7.
1. The qualification score is the sum of up to 12 Event Scores. The maximum possible qualification score is 12.000 for DL, 11.900 for the rest of the world.
2. A maximum of 4 Event Scores may be from multiops (MS/M2/MM).
3. A maximum of 4 Event Scores can be from outside an applicant’s home Selection Area (i.e., DXpeditions).
4. A maximum of 2 operators may submit scores for a single contest from a MS, 3 from a M2, and 4 from a MM.
5. If an operator’s call sign appears with more than one entry in a single qualifying event (e.g., from operating at more than one station), they may not use any scores from that contest.
6. In the unlikely case of a tie score for the final qualifying spot in a Selection Area, the applicants will be asked for additional scores beyond those submitted on the application until the tie is broken.