That would be an interesting study! My experience in the classroom is that students don't automatically transfer skills without explicit direction to use those skills and an explanation on how they apply in the new context, in the case that you mention, standardized tests.
Your mention of "on-line games"is rather broad. I'm guessing that each game or type of game would contribute to a different knowledge base and strategy set.
How would the learning be assessed?
This question seems redundant. If you are talking about how students use their game skills and apply them to standardized tests, then they are already being assessed with the standardized test...
If you were to do action research on this topic you would want to brainstorm with your kids the games they play and the knowledge and strategies they learn from them. You would need to take a look at the games to and see for yourself because, they do not have reflective thinking skills necessary to determine all the skills needed to play the game. Then show the kids how to use the same skills on the standardized test. Document their improvements and benchmark your class against another class to see if they showed significant improvement over the control class.
But your question about standardized tests and assessments brings about the most difficult question which the education systems world wide are facing. Most agree that there should be new assessment methods adopted to the new learning techniques. Regular standardized tests are a real problem.
I invite you to read more on my blog post and the discussion on classroom. I'd welcome your feedback.
Appreciated work, very impressive because it is related to human rights. I also like such kind of work and I also want to be a member of this research council. People like to listen news related to their rights.