Georgia HGN Test
In Georgia, the foundation for evidence based on a scientific principle or technique requires two findings regarding the evidence's reliability: such evidence is admissible upon a showing by the party offering the evidence that:
(1) the general scientific principles and techniques involved are valid and capable of producing reliable results and;
(2) the person performing the test substantially performed the scientific procedures in an acceptable manner. State v. Tousley, 271 Ga. App. 874, 876 (1) (a) (611 SE2d 139) (2005).
Georgia recognizes the HGN test as "an accepted, common procedure that has reached a state of verifiable certainty in the scientific community meeting the Harper v. State 249 Ga. 519 (292 SE2d 389) (1982) standard and is admissible as a basis upon which an officer can determine that a driver was impaired by alcohol." Tousley, 271 Ga. App. at 878 (1) (b) (i).
Nevertheless, the State "must still satisfy the second component of the foundation, that is, that the tester 'substantially performed the scientific procedures in an acceptable manner.'" Id. at 879 (1) (b) (ii).