For screening purposes two types of polygraph exams exist, and either one or both exams may be administered.
A Counterintelligence Polygraph asks the candidate questions limited to those necessary to determine whether the examinee ever had any involvement with or knowledge of espionage/sabotage against the United States, unauthorized contact with representatives of a foreign government, or unauthorized disclosure of classified material. A Counterintelligence Polygraph is the most common polygraph. Within DoD, polygraph examinations used to determine initial eligibility for special assignment or special access are limited to counterintelligence questions.
A Lifestyle Polygraph asks the candidate questions the concern the subject's personal life and conduct and can involve all aspects of present and past behavior. Questions asked might concern drug and alcohol use, sexual misconduct, mental health, family relationships, compulsive or addictive behavior, and more. A Lifestyle Polygraph attempts to look for issues in a person's private life for which he or she might be susceptible to blackmail or coercion.
A Full Scope Polygraph is a combination of both the Counterintelligence and Lifestyle polygraphs.