Table 1. Experimental Testing of Youth Tobacco Inspections Protocols, 1980–May 22, 2015, N = 10.

Setting: Design	Standard Protocol	Alternative	Results
Cummings et al., 1996 [27]
Erie County, NY: Varied use of payment approach (youth paid for cigarettes) or termination approach (if clerk rang up sale, youth reported insufficient funds). Conducted in 1994 with 157 tobacco retailers. Same 16-year old boy used in all purchases. For both, when minor is asked age, he truthfully answered; when asked who cigarettes are for, he answered "me."	Enter store, pick up pack from display or ask clerk for Marlboros. (Purchasing pack is considered a successful sale.)	When pack is rung up by clerk, minor reports having inadequate funds. (Ringing up on the register is considered a successful sale.)	No difference between the two conditions, 61% payment, 68% no payment.
DiFranza, Coleman, and St. Cyr, 1999 [25]
Worcester, MA: Varied product purchased using three 16-year old boys, who each made 34 purchase attempts with rotation in order of products purchased at stores and order in which boys purchased products for a total of 292 attempts. Each attempt made by different boy and separated by a few weeks. Conducted in 1998.	Non-smoking male youths entered store alone and attempted to purchase, provided no ID, and answered questions about age honestly.	Alternated product purchased between cigarettes, smokeless, and cigars.	No difference in sales by type of product purchased: 53.5% cigarettes, 55.6% for cigars, and 50.0% for cigars.
			"Although the three youths were all 15-year-old non-smokers, their individual sales rates varied from 26.5–88.4% (p < 0.001). The youths were successful in 45.5% of the first third of their attempts, in 53.6% of the middle third, and in 60.4% of the final third of their attempts to purchase tobacco. The trend of increasing success over time was significant (p < 0.05)" (p. 323).
DiFranza, Savageau, and Bouchard, 2001 [8]
Eight communities, Massachusetts: Two attempts made on same day (within 30 minutes to standardize clerk) at 160 retailers, matched age, sex, and race/ethnicity. Order randomized.	Nonsmoking youth instructed to not wear heavy makeup or to appear older, stated true age, presented no ID; if refused, left quietly. Youth chooses brand. A bonus of $1 per completed sale was paid to the youth.	Young smokers natural behavior to buy tobacco in a new community: Current tobacco using youth allowed to dress as they chose, allowed to purchase other items while asking for cigarettes, allowed to lie about age, allowed to present own ID (not allowed to use fake ID). Could say anything to clerk except threats, expressions of anger, or profanity. Note only one girl had an ID. Youth chooses brand. Bonus of $1 per sale.	The odds of a sale were 5.7 times greater (95% CI: 1.5–22.0) in the alternative, more realistic protocol using smokers than in the standard protocol. This is controlling for sales clerk age, ID request, and community.
			"Smokers were almost twice as likely to be sold tobacco with no questions asked" (p. 230).
			Lying had little effect on results.
			ID effects may be confounded because only one youth had an ID.
Hyland, Cummings, and Seiwell, 2000 [21]
Chautauqua County, NY: One white female, age 15, attempted 76 purchases in a single October 1998 weekend. Half of outlets in each city were randomized to each protocol. Adult remained outside and minor requested a pack of Marlboro cigarettes.	Truthfully reported age if asked, reported not having an ID.	Minor told merchant she was 18 if asked.	No difference in rate of sales by protocol, p = 0.48.
Klonoff & Landrine, 2004 [20]
San Bernardino and Riverside County, CA: 1,600 purchase attempts in 232 stores with extensive training and seven waves of data collection, alternating standard protocol with alternative protocols to assess for secular trends. Each wave was separated by four to six weeks. Checks took place between 3 p.m. and 7 p.m. on weekdays and 9 a.m. and 4 p.m. on weekends. Racially/ethnically diverse participants, aged 15–17 (n = 21). All were non-smokers.	Standard protocol: "May I buy a pack of Marlboros, please?" If asked, cigarettes are for them, age is reported truthfully, and did not present ID.	Tested: (1) lie about age protocol, (2) note from dad protocol, (3) foot-in-door protocol. These are reported controlling for if the clerk requested ID. (1) "May I buy a pack of Marlboros, please? I'm 18." Youth repeatedly insisted being of age but would not produce an ID.	(1) Lying about age increased likelihood of sale, OR 4.22 (1.69–10.57)
		(2) "May I buy a pack of Marlboros, please? They're not for me, they're for my dad, here's a note from him." A fake note was presented.	(2) Note from dad decreased likelihood of sale, OR 0.13 (0.06–0.32)
		(3) Youth selected 2–3 items (e.g., soda/candy), placed on counter, waited until clerk began to ring up sale, and said "Oh, and a pack of Marlboros too please." Questions about age and who cigarettes were for were answered truthfully.	(3) Foot in the door purchase of sundries had no impact on sale, OR 0.88 (0.35–2.22).
			All manipulative conditions compared to standard, x2 = 4.408, df = 1, n = 1600, p < 0.04.
			Other than in the note from dad (which clerks "typically laughed at," p. 521) and rejected, requests for ID were lowest in the foot in the door protocol. Requesting ID was the strongest predictor of not selling.
Landrine & Klonoff, 2003 [19]
San Bernardino and Riverside County, CA: Based on interviews with youth smokers, researchers designed an alternative protocol that was implemented by non-smoking youth age 15–17 in 232 randomly-selected tobacco retailers. Youth visited no more than seven retailers per week (one per day and one per clerk). Additional waves of data collection using the standard protocol (one prior, two after) were used to assess secular trends.	SAMHSA Synar Protocol: Enter store they are not known to and ask, "May I buy a pack of Marlboros, please?"	Familiarity protocol: Youths went to same store four times over six to eight days buying small items such as soda or candy from the same clerk and were friendly with the clerk. At visit five, youth then used standard protocol approach, walking up to register and asking, "May I buy a pack of Marlboros, please?"	Odds of a sale to a youth in the familiarity protocol were 5.51 (2.93–10.35) times greater than in the standard protocol.
			Authors note: "SAMSHA's prescribed method of sending youths into randomly selected stores where they are strangers must be modified to more accurately reflect youths' and merchants' behavior and hence actual youth access rates" (p. 1885).
Landrine, Klonoff, et al., 2001 [24]
22 cities, California: Non-smoking minors age 15–17 attempted purchase at three time points to assess secular trends in 674 purchase attempts at 227 randomly selected retailers.	"May I have a pack of Marlboros, please?"	"May I have a pack of Marlboros please—I have ID" with flash of real California state ID or driver's license.	Odds of sale in the flash ID protocol were 3.8 time higher (2.05–7.03) than in the standard protocol.
Levinson, Hendershott, and Byers, 2002 [23]
Six urban and suburban counties, Colorado: Non-smoking youths age 14–17 (n = 12, ten were male), most with previous compliance check experience, conducted 1,083 purchase attempts varying the presentation or non-presentation of a Colorado state ID (which notes the holder is under age 21). Males were clean shaven. Females wore no makeup. Adult supervisors were present in the store during the check.	If asked for ID, responded they didn't have one.	If asked for ID, provided actual ID.	When asked for ID, the ID condition had a relative risk 6.2 times more likelihood of sale than the no ID condition for a sales rate of: 12.2% (ID condition) vs. 1.9% (no ID condition). When standardized with covariates, RR 7.2 and sales rates of 12.6% v. 1.8%
			In final model with multiple covariates, odds of sale are 3.8 times greater for ID than no ID condition.
			Most (87.2%) clerks asked for an ID.
			"The current study suggests that the ID effect can increase cigarette sales to minors by nearly one third, even in locales where proof of age is usually required by clerks" (p. 298).
Levinson & Patnaik, 2013 [26]
Three counties, Colorado: Using standard Synar protocol in one urban, one suburban, and one resort county, researchers conducted test-retest reliability assessment (1079 checks) in a census of 671 tobacco retailers. Minors (four female, seven male) were age 15.5–16, with A/B grades, non-smokers, clean shaven (males) with no tattoos, makeup, and modest/casual dress. Could enter alone or with another minor, answer questions evasively, buy snack or drink, use ID or not, and visit store several times before attempted purchase. Adults could stay outside or enter.	One check	Back-to-back checks separated by an average of 22.5 days. Note: Following classical test theory, unreliability in tests can be reduced by increasing the number of tests of the same construct	A single visit produced a retailer violation rate of 16.8% (first visit) or 15.7% (second visit); however, combining both visits produced a retailer violation rate of 25.3%.
			Purchase of a snack is associated with greater odds of sale, OR 2.50 (1.13–5.54)
			Odds of violation increased with minor experience.
Schmidt, 2001 [22]
Baltimore, MD: Using a convenience sample of stores from a commercial list, conducted 237 checks. Three conditions to assess the role of purchase of an additional item with cigarettes.	Racially concordant pairs of girls, age 16.5–17.5, entered a store together. One of the pair attempted to purchase cigarettes in alternating fashion. All were non-smokers. White girls asked for "a pack of Marlboro Reds" and Black girls for "a pack of Newports." Answered questions about age truthfully, showed ID if asked.	Three conditions: (1) Purchase with adult item (i.e., newspaper), (2) purchase with small bag of potato chips, and (3) no co-purchase (i.e., control).	No difference in sale rate between three conditions, x2, df = 2, n = 237) = 0.213.