Err, no. Completion percentage is not accuracy. Also did it ever cross your mind that football was played differently in 2015 than in 1998? Modern college QBs throw shorter passes designed to get receivers the ball in space; last century they threw fewer but longer passes and mostly to pick up first downs. Which is why McNabb's completion percentage ranking higher, as well as his yards per attempt being a full yard more than Prescott's, are important details. McNabb was the more accurate QB for his era, which is all you can compare. You can't compare numbers across eras, or Joe Flacco would be better than Roger Staubach.
In 1997, Paul Pasqualoni, McNabb's head coach at Syracuse installed the West Coast passing scheme.
Pasqualoni contacted Mike Holmgren and then-offensive coordinator for Green Bay Andy Reid, and watched Packer film and Packer practice.
McNabb was schooled in the short-passing game while at Syracuse.
McNabb averaged 1 (.9 to be exact) yard per attempt more than Prescott -- hardly an indication that McNabb threw longer passes.
And by the way, Prescott played in the SEC, while McNabb playing those "powerhouse football teams" in the Big East - Temple, Boston College, Rutgers, & Pittsburgh.
In football, if a QB delivers the ball (completion) without mistakes, I say the QB is accurate.