ESPN's Football Power Index (FPI) is a simulation-based ranking system designed to measure the relative strength of teams. In 2014, Texas A&M was ranked #16 in the preseason (with a projected record of 7.8-4.2) and finished at #23 after going 8-5. The 2015 preseason FPI ranks the Aggies at #11, which is also fifth in the SEC West. The overall defensive rank of 37th for A&M seems high, but hopefully new defensive coordinator John Chavis can make fielding a top 50 defense a reality. A&M's offense is ranked 4th which is less surprising with a lot of returning talent all over the field.
According to ESPN, the FPI is calculated using the prior season's rankings on offense, defense and special teams; returning starters and head coach information; and recruiting rankings.