The 1970 Field Representative's Manual instructed interviewers to "[e]xclude marijuana, a type of wild tobacco, (also called "pot" or "grass')" when accepting responses to the smoking-related questions.

According to the 1970 Manual, if respondents volunteered that they smoked cigarettes made of non-tobacco products, "such as lettuce or cabbage leaves," interviewers were to rephrase the question to, "Excluding any nontobacco cigarettes, have you smoked at least...?"

The 1997-2000 Field Representative's Manuals stated, "The questions in this section concern cigarette smoking only. Accept whatever the Sample Adult reports, except if it is volunteered that he/she smoked a pipe, cigars of any kind, marijuana, hashish, 'crack', or the like." The Manuals for 2001 forward define a cigarette as "anything the respondent reports except cigars or any kind of marijuana."

The 1970 Field Manual states that one hundred cigarettes is equal to five packs, but instructs interviewers to "ask the question as worded because the respondent might misinterpret 'five packs' as referring to five packs a day.

In 1997 forward respondents who answered "Yes" in SMOKEV (Ever smoked 100 cigarettes in life) were asked, "Do you now smoke cigarettes every day, some days, or not at all?" (SMOKFREQNOW). Depending on their response in SMOKFREQNOW, respondents were also able to receive one or more of the following questions in 1997 forward:

• "On the average, how many cigarettes do you now smoke a day?" (CIGSDAY1)

• "On how many of the past 30 days did you smoke a cigarette?" (CIGDAYMO)

• "On the average, when you smoked during the past 30 days, about how many cigarettes did you smoke a day?" (CIGSDAY2)

The variable CIGSDAY (Average number of cigarettes smoked per day: Current Smokers) is available for 1970, 1976-1977, and 1997 forward. The variable SMOKAGEREG (available for 1970 and 1997 forward) reports the age at which respondents first started to smoke "fairly regularly."