So I'm trying begin to differentiate between the statistical profiles of different defensive alignments; what are the statistical tendencies (in terms of footprint, not quality) of a 3-4 versus a 4-3? That sort of thing. But before I can begin to go down this road, I need to figure out the base defense for each FBS team. Below is the list I compiled. Please let me know if corrections need to be made.
(And yeah, some teams' use of hybrids purposefully blur the line between one base and another. Such is life.)
| Defense | Base | Defense | Base | Defense | Base |
| Air Force | 3-4 | Iowa State | 4-3 | Rice | 4-3 |
| Akron | 4-3 | Kansas | 3-4 | Rutgers | 4-3 |
| Alabama | 3-4 | Kansas State | 4-3 | San Diego State | 3-3-5 |
| Arizona | 4-3 | Kent State | 4-3 | San Jose State | 4-3 |
| Arizona State | 4-3 | Kentucky | 4-3 | SMU | 3-4 |
| Arkansas | 4-3 | Louisiana Tech | 4-3 | South Carolina | 4-3 |
| Arkansas State | 4-3 | Louisville | 4-3 | South Florida | 4-3 |
| Army | 3-4 | LSU | 4-3 | Southern Miss | 4-3 |
| Auburn | 4-3 | Marshall | 4-3 | Stanford | 3-4 |
| Ball State | 4-3 | Maryland | 4-3 | Syracuse | 4-3 |
| Baylor | 4-2-5 | Memphis | 4-3 | TCU | 4-2-5 |
| Boise State | 4-2-5 | Miami-FL | 4-3 | Temple | 4-3 |
| Boston College | 4-3 | Miami-OH | 4-3 | Tennessee | 4-3 |
| Bowling Green | 4-3 | Michigan | 4-3 | Texas | 4-3 |
| Buffalo | 3-4 | Michigan State | 4-3 | Texas A&M | 3-4 |
| BYU | 3-4 | Middle Tennessee | 4-3 | Texas Tech | 4-2-5 |
| California | 3-4 | Minnesota | 4-3 | Toledo | 4-3 |
| Central Florida | 4-3 | Mississippi State | 4-3 | Troy | 4-3 |
| Central Michigan | 4-3 | Missouri | 4-3 | Tulane | 4-3 |
| Cincinnati | 4-3 | Navy | 3-4 | Tulsa | 4-3 |
| Clemson | 4-3 | N.C. State | 4-3 | UAB | 4-3 |
| Colorado | 4-3 | Nebraska | 4-3 | UCLA | 4-3 |
| Colorado State | 4-3 | Nevada | 4-3 | UL-Lafayette | 4-3 |
| Connecticut | 4-3 | New Mexico | 4-2-5 | UL-Monroe | 3-3-5 |
| Duke | 4-3 | New Mexico State | 4-3 | UNLV | 4-3 |
| East Carolina | 3-4 | North Carolina | 4-3 | USC | 4-3 |
| Eastern Michigan | 4-3 | North Texas | 4-3 | Utah | 4-3 |
| Florida | 4-3 | Northern Illinois | 4-3 | Utah State | 3-4 |
| Florida Atlantic | 3-4 | Northwestern | 4-3 | UTEP | 4-3 |
| Florida International | 4-3 | Notre Dame | 3-4 | Vanderbilt | 4-3 |
| Florida State | 4-3 | Ohio | 4-3 | Virginia | 4-3 |
| Fresno State | 4-3 | Ohio State | 4-3 | Virginia Tech | 4-3 |
| Georgia | 3-4 | Oklahoma | 4-3 | Wake Forest | 3-4 |
| Georgia Tech | 3-4 | Oklahoma State | 4-3 | Washington | 4-3 |
| Hawaii | 4-3 | Ole Miss | 4-3 | Washington State | 4-3 |
| Houston | 3-4 | Oregon | 4-3 | West Virginia | 3-3-5 |
| Idaho | 4-3 | Oregon State | 4-3 | Western Kentucky | 4-3 |
| Illinois | 4-3 | Penn State | 4-3 | Western Michigan | 4-2-5 |
| Indiana | 4-3 | Pittsburgh | 3-4 | Wisconsin | 4-3 |
| Iowa | 4-3 | Purdue | 4-3 | Wyoming | 4-3 |