There are only three tests approved by the United States Department of Transportation as sufficiently standardized to offer reliability in roadside testing for intoxication. These standardized DUI field sobriety tests are the Horizontal Gaze Nystagmus, the one-leg stand, and the 9 step walk and turn. In addition to these test, Massachusetts police officers may ask a motorist who is suspected of operating under the influence to recite the alphabet starting with the letter “E,” for example, and stopping with the letter “P.” The police officer administering the Natick MA alphabet field sobriety test will instruct the driver to recite the alphabet without singing. A variation of this test is called the Romberg alphabet test, where the DUI suspect is told to stand with arms to the side, eyes closed and head tilted back and recite the alphabet or count, forward or backward, for the equivalent of 30 seconds in a non-rhythmic fashion.
No valid study has supported as the alphabet test as a legitimate and reliable sobriety test. Nevertheless, these "tests" are sometimes mis-identified as field sobriety evaluations. The NHSTA Field Sobriety Testing Manual cautions police officers regarding the Natick Mass DUI alphabet test, because it is not one of the standardized tests.