We've said before that, based on various statistics especially yards per carry, Charles is the most effective running back in the NFL. On that note alone, it's good that Chiefs head coach Todd Haley plans to give Charles more carries this season.
Charles not only gets over six yards per carry, but also gets first downs, too. I'm sure we've talked about this before but NFL.com recently published a study (as pointed out by Spiderwomn69) looking at last season's top 10 running backs and on what percentage of their carries they earn a first down.
That would belong to Charles who gets a first down on just over 30 percent of his carries. Touchdowns are certainly nice but you generally get into the end zone through multiple first downs.
Check out the chart at NFL.com to visualize Charles' dominance.