This description of the One Leg Stand test posted by California DUI Lawyer.

The final scoring factor is hopping on one foot. This can be scored only if they resort to hopping on the anchor foot in order to maintain balance. It should not be scored if the suspect is having difficulty such as moving the anchor foot back and forth. The suspect can receive a maximum score on this test in two ways. This is when the suspect puts their foot down three or more times during the thirty second count or otherwise demonstrates that they can not do the test. The officer must be able to articulate why they felt the defendant could not do this test. The degree of reliability attached to this test if it is demonstrated and scored properly is 65 percent. The officer is trained to use this as probable cause to arrest the suspect for DWI.

The training of the officer and the training manual advises that for purposes of the arrest report and courtroom testimony, the officer is trained that it is not simply enough to report the suspect's "score" on the three tests. The numeric scores are only important to the police officer in the field to determine probable cause. It is insufficient to secure a conviction, and must be accompanied by more descriptive evidence. The officer is trained that they must be able to describe how the suspect performed, and exactly what the suspect did when he or she performed the test and when these clues occurred. The manual provided to the officer has a standard note-taking guide which is recommended to be utilized to assist the officer and prove the case.

In conclusion, the three tests we have covered, are essentially the Standard that all field sobriety tests can be compared to. These tests have in the past been demonstrated to be sensitive at the .10% BAC threshold and most recently studies have revealed degrees of reliability at .08% BAC. Nowhere in any of these tests does the officer require that the suspect close their eyes to perform the test. This will invalidate the reliability of any test.