Table 5. Understanding of study design and randomisation^*.

Developed country studies			Developing country studies
Author	Country	Understood study design	Author	Country	Understood study design
Van Stuijvenberg et al, 199853	The Netherlands	88% placebo design	Moodley et al, 200527	South Africa	49% knew they had a 50% chance of receiving placebo; 19% understood placebo
Criscione et al, 200344	USA	87% placebo design	Hill et al, 200823	Ghana	13% understood ‘not all trial capsules were the same’
Howard et al, 198163	USA	86% double blind design	Leach et al, 199933	The Gambia	10% placebo design†
Harrison et al, 199555	USA	79%
Pope et al, 200346	Canada	76% placebo design
Bergler et al, 198064	USA	64% (at start), 28% (3 months later)
Developed country studies			Developing country studies
Author	Country	Understood randomisation	Author	Country	Understood randomisation
Ravina et al, 201036	USA	90%, yet only 67% understood there was a 1 in 3 chance of receiving placebo	Ellis et al, 201018	Mali	80% of adults 90% of parents
Simon et al, 200348	USA	68% of majority English speakers	Krosin et al, 200626	Mali	68%
		26% of minority English speakers
		14% of minority non-English speakers
Bergenmar et al, 200837	Sweden	85%	Pace et al, 200528	Thailand	31%
Gammelgaard et al, 200441	Denmark	79%	Moodley et al, 200527	South Africa	21%
Criscione et al, 200344	USA	50%	Pace et al, 200529	Uganda	19%
Van Stuijvenberg et al, 199853	The Netherlands	50%
Kodish et al, 200442	USA	50%
Howard et al, 198163	USA	43%
Pope et al, 200346	Canada	39%
Benson et al, 198560	USA	33% of depression study, 16% of schizophrenia study
Hietanen et al, 200051	Finland	23%
Schats et al, 200347	The Netherlands	22%

^*Arranged from highest to lowest %.

^†When broken down into those who had received a written information sheet at least a week before consent, 15% of those who had received the sheet understood that there was a placebo group versus 4% of those who had not received prior written information.