This is an excellent interview by the BBC Radio's and Seahawks Draft Blog's Rob Staton (also of Field Gulls Draft Hangouts fame). Seahawks sports scientist Dean Riddle talks about his start at Nike with the SPARQ program, his journey into rugby league, cricket, and then soccer in Europe, ending up with his eventual landing spot in Seattle. He talks about how the SPARQ rating was created and how it's utilized by organizations.
From his experience: "The SPARQ rating is incredibly accurate... There's a really strong correlation between a higher SPARQ rating score and success" in soccer. He adds that the SPARQ rating also has "an incredibly high correlation [to success] in football, hockey, basketball.