Determining the impact of smoking point of sale legislation among youth (Display) study: a protocol for an evaluation of public health policy

Table 2 Estimated sample sizes and smoking prevalence and incidence by age and year group

Age group/Grade	% pupils in each class¹	N pupils per school	Tot no pupils 4 schools	Estimated response rates²		Prevalence regular smoking³		Incidence regular smoking	Prevalence ever smoked		Incidence ever smoked
				%	N	%	N		%	N
School Surveys 2013-14
13/S2	100%	188	752	85%	640
15/S4	100%	188	752	85%	640
Total all schools		376	1504	85%	1280
Total per school			376	85%	320
School Surveys 2015-17
12/S1	18.1%	217	866	85%	736	1.0%	7	1.0%	4%	26	4%
13/S2	18.3%	220	878	85%	747	4.8%	35	3.8%	23%	168	19%
14/S3	18.8%	225	902	85%	767	11.0%	84	6.3%	35%	268	13%
15/S4	18.8%	225	901	85%	766	16.5%	126	5.5%	44%	333	9%
16/S5	15.7%	189	754	85%	641	20.0%	128	3.5%	47%	298	3%
17/S6	10.2%	123	491	85%	417	24.0%	100	4.0%	47%	194	0%
Total all schools		1198	4793		4074		482			1287
Per School			1198		1018		120			322

1. Distribution of pupils over different age groups is based on most recent School statistics released by Scottish Government.
2. Response rates are based on HBSC survey experience.
3. Regular smoking defined as weekly smoking. Percentage 13 and 15-year old based on SALSUS, Percentages 12, 14, 16 and 17-year olds based on plotting, making use of HBSC smoking data for 11-year olds, SALSUS 13 and 15-year olds and 17-year olds’ data from the Scottish health survey (16-24-year olds: Male 24%; Female 29%) [18–20].

ISSN: 1471-2458