Table 2.

Baseline Characteristics of Weighted Follow Up Sample, with Comparison to Baseline Values of Full, Baseline Sample.

	Follow up sample (n = 582)	Baseline (n = 3770)
Used marijuana in past 30 days Question: “On how many occasions (if any) have you used marijuana (weed, pot) or hashish (hash, hash oil) in the past 30 days?” Coded 1 for any response greater than zero.	.23 (.17−.28)	.21 (.18−.25)
Binged drank in past two weeks Question: “Think back over the LAST TWO WEEKS. How many times have you had five or more drinks in a row? (A "drink" is a bottle of beer, a glass of wine, a wine cooler, a shot glass of liquor, a mixed drink, etc.)” Coded 1 for any response greater than zero.	.17 (.12−.22)	.17 (.12−.21)
Vaped nicotine in past 30 days Question: “On how many DAYS (if any) have you vaped NICOTINE during the last 30 days?” Coded 1 for any response greater than zero.	.24 (.19−.29)	.25 (.19−.31)
Availability of Substances
Easy to get marijuanaa Question: How difficult do you think it would be for you to get each of the following types of drugs, if you wanted some… Marijuana (pot, weed)?” Coded 1 for marked response of “Fairly Easy” or “Very Easy”	.76 (.67−.85)	.75 (.69−.80)
Easy to get alcoholb Question: How difficult do you think it would be for you to get each of the following types of drugs, if you wanted some… Alcohol?” Coded 1 for marked response of “Fairly Easy” or “Very Easy”	.86 (.77−.95)	.81 (.77−.85)
Easy to get vaping devicea Question: “To "vape" is to use a device such as a JUUL, vape-pen, e-cigarette, e-hookah, or e-vaporizer to inhale a vapor into the lungs. How difficult do you think it would be for you to get each of the following, if you wanted some… Vaping device (JUUL, e-cigarette, e-pen, etc.)?” Coded 1 for marked response of “Fairly easy” or “Very Easy”	.73 (.63−.82)	.75 (.70−.80)
Female Question: “What is your sex?” Coded 1 for response of ‘female.’	.51 (.45−.57)		.50 (.45−.54)
Non-Hispanic White Question: How to you describe yourself (Select one or more responses)? Coded 1 for respondents who marked only “White (Caucasian)” and did not mark Hispanic.	.48 (.42−.54)		.49 (.33−.64)
Grade point average Question: Which of the following best describes your average grade so far in high school? 1="A (93−100)" 2="A- (90−92) 3="B+ (87−89)" 4="B (83−86)" 5="B- (80−82)" 6="C+ (77−79)" 7="C (73−76)" 8="C- (70−72)" 9="D (69 or below)"	3.38 (3.08−3.69)		3.22 (2.93−3.50)
Parent has college degree Questions: “What is the highest level of schooling your father completed?” and “What is the highest level of schooling your mother completed?” Coded 1 for a marked response of “Completed college” or “Graduate or professional school after college” for either father or mother	.52 (.46−.58)		.54 (.44−.64)
Social distancing practices at follow upc
Extreme Question: “Have you met friends in person since the pandemic started”? Coded 1 for response of “No.”	.20 (.16–.25)		n/a
High Questions: “When you are with your friends who do not live with you, how often do you stay six feet apart from them?” and “When you are with your friends who do not live with you, how often do you wear a facemask?” (Questions asked only of those who had met with friends in person since the pandemic started). Coded 1 for respondents whose answers were “Always or almost always” or “Often” for both questions.	.18 (.14–.23)		n/a
None to medium Coded 1 for respondents who answers to either of the questions above for category above included “Never”, “Rarely,” or “Sometimes.”	.61 (.55–.67)		n/a

Note: None of the estimates significantly differed across the two columns at p < .05.

^aQuestion asked of a randomly-selected one-third of sample at baseline and of all respondents at follow up.

^bQuestion asked of a randomly-selected one-sixth of sample at baseline and of all respondents at follow up.

^cReported means are percentage of respondents in each category. Combined percentages do not add to 100 % because of rounding.