I found this in a story about Jason Ness that gives some insight into the committees decision. From this it looks like dominance as rated by pinning percentage seems to be the deciding factor, after being an undefeated national champion.
Ness pinned 19 of 31 opponents for a stingy pinning percentage of 61 percent, including 13 of his first 14 opponents. Sixteen of the 19 pins came in the first period for the Bloomington, Minnesota native. The two runner-ups for this year’s Hodge Trophy were Iowa State’s Jake Varner and Iowa’s Jay Borschel, champs at 197 and 174 respectively. Varner won his second straight national title, finishing 32-0. Borschel capped a perfect 37-0 season with his first NCAA crown.
But the reason Ness was selected over Varner and Borschel was the number of pins he had, nearly doubling both his counterparts. Varner and Borschel both finished the year with 10 apiece. Borschel’s pinning percentage was 27 percent, Varner’s 31 percent. Varner has had better past credentials than Ness as a four-time finalist, but the award is a single-season award. Past credentials are used in tiebreaker situations where pin numbers, for example, are nearly equal.