Blue and Red stars?

[Volkner]

Can someone explain the rating system please? ... or point me somewhere where it is explained? I'd like to know what the difference is between the blue stars and the red stars.

Thanks

[ibag]

The blue stars show the difficulty estimated by the author. After a puzzle is rated at least 10 times by the solvers, the red stars appear and give the average difficulty given by the solvers.

[Volkner]

The blue stars show the difficulty estimated by the author. After a puzzle is rated at least 10 times by the solvers, the red stars appear and give the average difficulty given by the solvers.

Thanks.