The new if race is sanctioned and meets records standards was a simple and quick solution to help avoid confusion with courses and records. Previously, the Record Eligible field displayed either a yes or no. Later, it was changed to a yes, if sanctioned and no. From that information a race director might, incorrectly assume the mile was a record event. (The mile american record was dropped several years ago.)
A similar situation could occur with race walk loops. Not too long ago, a certified 833.33 meter, closed loop would display yes, if sanctioned in the record eligible field. A rule changes introduced a few years ago required race walk loops be a minimum of 1000 meters for championship and record eligible events. (Race walks records also have limit to the length of the loop. Race walk events longer than 10 km may have a maximum course length of 2500 meters. Events less than 10km may have a maximum distance of 1250 meters.)
The point is, simply finding a certified course that has a separation of no more than 50% and drop that does not exceed 1 part per thousand does not mean the course may be used for setting American records. Additionally, the rules for records change from year to year. The complete list of requirements for setting American records is listed in the USATF Competition Rules book, starting with Article V. The rule books are available online at the link below.
http://www.usatf.org/groups/of...als/resources/rules/
Thank you. -- Justin