Table 1. Weighted estimates of percentages of past-year substance users that used in various social contexts and means describing frequencies of use in each context, for six mutually exclusive subgroups of high school seniors in the United States based on past-year substance use behavior (Source: Monitoring the Future Study 2002-2011).

Social contexts	Past-year users of multiple substances % (SE) [Mean (SE)]	Past-year users of alcohol only % (SE) [Mean (SE)]	Past-year users of marijuana only % (SE) [Mean (SE)]	Past-year nonmedical users of prescription stimulants only % (SE) [Mean (SE)]	Past-year nonmedical users of prescription tranquilizers only % (SE) [Mean (SE)]	Past-year nonmedical users of prescription opioids only % (SE) [Mean (SE)]	Design-Based Rao-Scott Chi-Square p-value
Location (Where)
At school	31.4 (0.6) [1.3 (<0.1)]	4.5 (0.3) [1.1 (<0.1)]	16.8 (2.3) [1.3 (<0.1)]	45.4 (8.2) [2.0 (0.2)]	12.6 (7.4) [1.3 (0.2)]	25.2 (6.9) [1.4 (0.1)]	p < 0.001
At your home (or apartment)	76.8 (0.6) [2.1 (<0.1)]	50.1 (0.7) [2.0 (<0.1)]	42.0 (3.0) [1.9 (<0.1)]	83.1 (5.4) [3.7 (0.2)]	63.6 (12.3) [3.1 (0.5)]	72.7 (7.5) [3.0 (0.3)]	p < 0.001
At a party	93.0 (0.3) [3.0 (<0.1)]	75.5 (0.6) [2.9 (<0.1)]	58.9 (2.9) [2.3 (<0.1)]	10.2 (4.2) [1.3 (0.1)]	15.1 (8.8) [1.3 (0.2)]	11.7 (5.3) [1.3 (0.1)]	p < 0.001
In a car	74.7 (0.6) [2.0 (<0.1)]	17.3 (0.5) [1.3 (<0.1)]	58.7 (2.9) [2.2 (<0.1)]	17.2 (5.3) [1.4 (0.2)]	14.0 (8.1) [1.3 (0.2)]	24.4 (8.0) [1.5 (0.2)]	p < 0.001
People present (Who)
When you were alone	54.2 (0.6) [1.6 (<0.1)]	17.2 (0.5) [1.3 (<0.1)]	37.7 (2.9) [1.6 (<0.1)]	56.5 (8.4) [2.6 (0.3)]	28.9 (10.6) [1.7 (0.3)]	53.6 (8.0) [2.1 (0.2)]	p < 0.001
With 1 or 2 other people	96.2 (0.2) [2.8 (<0.1)]	67.4 (0.6) [2.2 (<0.1)]	89.4 (1.9) [3.1 (<0.1)]	44.9 (8.5) [2.0 (0.3)]	59.8 (13.2) [2.8 (0.5)]	53.9 (8.3) [2.3 (0.2)]	p < 0.001
People over age 30	68.8 (0.6) [1.8 (<0.1)]	55.5 (0.7) [2.1 (<0.1)]	28.5 (2.7) [1.6 (<0.1)]	39.5 (8.5) [2.1 (0.3)]	78.5 (9.1) [3.6 (0.4)]	72.0 (7.0) [2.5 (0.2)]	p < 0.001
Date or spouse	67.8 (0.6) [2.0 (<0.1)]	37.9 (0.6) [1.7 (<0.1)]	36.3 (2.8) [1.8 (<0.1)]	19.8 (6.9) [1.4 (0.2)]	14.7 (8.2) [1.5 (0.3)]	15.9 (5.5) [1.4 (0.2)]	p < 0.001
Time of day (When)
During daytime (before 4pm)	74.3 (0.6) [2.0 (<0.1)]	21.7 (0.5) [1.3 (<0.1)]	56.7 (2.9) [2.1 (<0.1)]	83.9 (5.3) [3.4 (0.3)]	77.9 (9.3) [3.2 (0.4)]	56.1 (8.4) [2.3 (0.2)]	p < 0.001

Note: The sample size for users of multiple substances in the past year was 8352, and sample sizes ranged from 8097 to 8190 for past-year alcohol users only, 372 to 376 for past-year marijuana users only, 47 to 49 for past-year stimulant users only, 17 to 19 for past-year tranquilizer users only, and 43 to 47 for past-year opioid users only due to missing data. SE = linearized estimate of standard error.

Note: The question used for each social context was as follows: “When you used [substance] during the last year, how often did you use them in each of the following situations?” Response options included: (1) not at all, (2) a few of the times, (3) some of the times, (4) most of the times, and (5) every time.

Note: The question used for each substance was as follows: “On how many occasions (if any) have you used (substance) during the last 12 months?” The items pertaining to controlled medications further specified “…on your own—that is, without a doctor telling you to take them.” Response options ranged from (1) 0 occasions to (7) 40 or more occasions.