Latest contests refereeing is the subject being discussed widely.
So how the contest refereeing is being made?
Initially it is the computer analysis.
It means all the logs are loaded into the computer, then cluster spots data are loaded into the computer also.
This makes the material for the initial analysis and then the contest committee uses its own tools.

Here you can see two CQ WW DX CW 2008 logs,

RZ9OZO log (op. RW1AC) computer log analysis

EF8M log (op. RD3AF) computer log analysis

Thanks to "For Fair Contesting" group for the material given.
http://contesting.at-communication.com/en