Table 5

Understanding of study design and randomisation*

Developed country studiesDeveloping country studies
AuthorCountryUnderstood study designAuthorCountryUnderstood study design
Van Stuijvenberg et al, 199853The Netherlands88% placebo designMoodley et al, 200527South Africa49% knew they had a 50% chance of receiving placebo; 19% understood placebo
Criscione et al, 200344USA87% placebo designHill et al, 200823Ghana13% understood ‘not all trial capsules were the same’
Howard et al, 198163USA86% double blind designLeach et al, 199933The Gambia10% placebo design
Harrison et al, 199555USA79%
Pope et al, 200346Canada76% placebo design
Bergler et al, 198064USA64% (at start), 28% (3 months later)
Developed country studiesDeveloping country studies
AuthorCountryUnderstood randomisationAuthorCountryUnderstood randomisation
Ravina et al, 201036USA90%, yet only 67% understood there was a 1 in 3 chance of receiving placeboEllis et al, 201018Mali80% of adults
90% of parents
Simon et al, 200348USA68% of majority English speakersKrosin et al, 200626Mali68%
26% of minority English speakers
14% of minority non-English speakers
Bergenmar et al, 200837Sweden85%Pace et al, 200528Thailand31%
Gammelgaard et al, 200441Denmark79%Moodley et al, 200527South Africa21%
Criscione et al, 200344USA50%Pace et al, 200529Uganda19%
Van Stuijvenberg et al, 199853The Netherlands50%
Kodish et al, 200442USA50%
Howard et al, 198163USA43%
Pope et al, 200346Canada39%
Benson et al, 198560USA33% of depression study, 16% of schizophrenia study
Hietanen et al, 200051Finland23%
Schats et al, 200347The Netherlands22%
  • * 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.