Characteristic Study ID	Measurement period			Study population	Intervention group	Control group	Overall effect	Comments
Colin‐Ramirez 2010	Baseline			498 boys and girls	84	84	‐	‐
	Follow‐up (12 months post‐intervention)				85	89	NS
Burke 1998	Enrichment group boys	Baseline		720 boys and girls	NA	NA	NS	Self‐reported time spent watching TV Time spent watching TV returned almost to baseline levels after the intervention in all groups, except in boys in the enrichment group
		End of intervention			NA	NA	NS
		Follow‐up (6 months)			18	23	P = 0.014
	Enrichment group girls	Baseline			NA	NA	NS
		End of intervention			NA	NA	NS
		Follow‐up (6 months)			2	5	NS
Gentile 2009	Child report	Baseline		1029 boys and girls	245.1	262.3		Time spent viewing TV and playing video games was assessed by children, using methods that have been used reliably with children. Time spent on TV and video games was summed to create weekly screen time (hours/week)
		Follow up (6 months)			238.3	249.4	NS
	Parent report	Baseline			180	197.1
		Follow up (6 months)			205.7	222.9	P < 0.05 Cohen's d 1.38 = 2 hours less screen time in favour of experimental group
Haerens 2006	Boys	Baseline		2434 boys and girls	33.9	53.4	‐	Self‐reported amount of time spent watching TV
		End of intervention (year 2)			34.6	35.0	P<0.05
	Girls	Baseline			20.5	24.8	‐
		End of intervention (year 2)			18.7	22.9	NS
Jones 2008	Baseline			606 girls	137	114	NA	Sedentary activity data were collected using multiple administrations of the Self‐Administered Physical Activity Checklist (SAPAC), as well as with the Calcium, Osteoporosis and Physical Activity (COPA) questionnaire. The SAPAC had an additional section for sedentary activities such as TV and video watching at 3 time periods during the previous day It is worth noting that the control group spent a lot more time in sedentary behaviours at follow‐up than they had at baseline, and also that the control group had much lower sedentary behavior at baseline than the intervention group
	End of intervention				135	152	P = 0.04 17 (95% CI 16.5 to 17.5)
Kipping 2008	Weekdays	Baseline		604 boys and girls	150	135		Self reported time spent engaged in screen‐based activities. Child self‐report about the length of time spent doing screen‐based activities on the previous weekday and Saturday
		End of intervention			NA	NA	P = 0.62 ‐12 (95% CI ‐43 to 19)
	Weekends	Baseline			150	180	‐
		End of intervention			NA	NA	P = 0.42 ‐15 (95% CI ‐58 to 27)
Lubans 2009	Baseline			106 boys and girls	150	131.4	NS	Sedentary behaviors were assessed using a questionnaire. The items were adapted from the Adolescent Sedentary Activity Questionnaire used in the NSW Schools Physical Activity and Nutrition Study (SPANS)
	Follow up (6 months)				124.8	135.6	NS
Neumark‐Sztainer 2009	Baseline			96 boys and girls	NA	NA	NS	Children were asked on one average weekday and Saturday or Sunday, how many hours are spent watching TV/videos; 7 response options ranging from 0 to 6+ hours
	End of intervention				136.8	140.4	P = 0.857
Neumark‐Sztainer 2010	Baseline			336 adolescent girls	168	144	NS	TV viewing for 30 min blocks/day. Overall there was a change in sedentary behaviors, but not for TV viewing
	Follow‐up (5 months post‐intervention)				137.4	140.4	P = 0.883
Peralta 2009	Baseline			32 boys	387	315	NS	Time spent in small screen recreation on weekends was assessed using the Adolescent Sedentary Activities Questionnaire. Participants were asked to report (in hours) TV viewing, video viewing, video game, computer game/Internet use, and computer use for homework
	Follow up (6 months)				285	287.7	P = 0.56 12 (95% CI ‐306 to 168)
Robinson 1999	Child report	TV	Baseline	192 boys and girls	132	132.8	‐	Self‐reported time spent in sedentary activities
			End of intervention		77.1	124.3	P < 0.001
		Videotapes	Baseline		40.3	47.1	‐
			End of intervention		30	44.6	NS
		Video games	Baseline		22.3	33.4	‐
			End of intervention		11.4	36	P = 0.01
		Other sedentary behaviors	Baseline		40.3	38.6	‐
			End of intervention		32.6	35.1	NS
	Parental report	TV	Baseline		102.9	128.6	‐
			End of intervention		77.1	128.6	P < 0.001
		Videotapes	Baseline		42.9	37.7	‐
			End of intervention		33.1	33.5	NS
		Video games	Baseline		15.4	23.1	‐
			End of intervention		12	22.3	NS
		Other sedentary behaviors	Baseline		385.7	342.9	‐
			End of intervention		351.4	368.6	NS
Salmon 2008	Intervention 1	Baseline		268 boys and girls	NA	NA	‐	Child self‐report time (hours/minutes) engaged in TV viewing, computer use and playing electronic games. Each of these variables was summed and divided by 7 to calculate average minutes per day Baseline data available for boys and girls; however, not available for whole sample. Results only available post intervention for whole sample. Statistically significant effect observed for Behavior Modification arm, in favor of the control group
		Follow‐up (12 months)			NA	NA	NS
	Intervention 2	Baseline			NA	NA	‐
		Follow‐up (12 months)			NA	NA	P < 0.05 (BM)
	Intervention 3	Baseline			NA	NA	‐
		Follow‐up (12 months)			NA	NA	240 (95% CI 28 to 452)
Simon 2004	% time in high sedentary activities	Baseline		954 adolescent boys and girls	34%	27%	‐	Self‐reported time spent in sedentary activities such as TV viewing and video games. High sedentary behaviour ≥ 3 h/day TV viewing and computer/video games
		During intervention (6 months)			28%	36%	P < 0.0001 OR 0.49 (95% CI 0.35 to 0.69)
	Minutes of TV viewing and computer/ video games	Baseline			108	104	‐
		End of intervention (year 4)			88	99	P < 0.02 ‐16 (95% CI ‐29 to ‐3)
Singh 2009	Boys	Baseline		875 boys and girls	268	294	NA	Screen‐viewing behavior (TV viewing and computer use), min/d assessed using a questionnaire pre tested for clarity and length among adolescents not participating in the study
		End of intervention Follow‐up (20 months)			258	278	P = 0.05 ‐25 (95% CI ‐50 to ‐0.3)
	Girls	Baseline			212	250	NA
		End of intervention Follow‐up (20 months)			258	248	NS ‐2 (95% CI ‐9 to 5)
Webber 2008	Baseline			36 schools all girls	456.5	458	NS ‐1.5 (95% CI ‐11 to 8)	Minutes of sedentary behavior defined as the number of minutes with less than light activity
	End of intervention (year 2)				511	514	NS ‐3.5 (95% CI ‐11 to 4)
	Program Champion– directed intervention (year 3)				524	533	P < 0.05 ‐8 (95% CI ‐17 to 0)
Williamson 2007	Baseline			586 boys and girls	HEE NA	ADT NA		The Self‐Administered Physical Activity Checklist (SAPAC) 34 is a 29‐item self‐report, 1‐day recall of physical and selected sedentary activities using a checklist format. The SAPAC was administered to small groups of students in a classroom setting. Self‐reported data from the SAPAC were summarized to measure minutes in sedentary pursuits
	End of intervention (18 months)				4	‐20	P = 0.4864
CI: confidence interval; NA: not acknowledged; NS: not significant; OR: odds ratio; TV: television; NSW: New South Wales; h/day: hours per day.