This database includes 710 RCTs from 46 countries published by 3811 researchers between 1986 and 2026.

Most, 580 (82%), are single-centred. The median (IQR) number of centres in the 130 multi-centred trials was 5 (2, 12.8) min=2 max=104.

The median (IQR) number of children in individually randomized trials was 61 (40, 106.8) min=6 max=2040 and 1523 (383.8, 3081) min=97 max=11661 in the 12 cluster randomized trials.

RCTs per year
RCTs per year (cumulative)
RCTs per year
Year RCTs
2026 14
2025 32
2024 21
2023 40
2022 32
2021 55
2020 49
2019 25
2018 41
2017 35
2016 25
2015 34
2014 21
2013 29
2012 26
2011 16
2010 11
2009 18
2008 13
2007 19
2006 10
2005 21
2004 8
2003 13
2002 17
2001 13
2000 8
1999 12
1998 7
1997 10
1996 9
1995 1
1994 5
1993 4
1992 4
1991 4
1990 2
1989 2
1988 2
1987 1
1986 1
Multicentre RCTs per year (cumulative)
Children randomized per year (cumulative)
RCTs and children randomized per country
Country RCTs Children randomized
United States 158 31757
India 99 10277
China 76 7545
Egypt 38 3214
Brazil 36 4718
Iran 30 2127
Turkey 30 2782
Canada 23 1851
United Kingdom 23 20657
Australia 22 4664
The Netherlands 20 2047
Germany 15 1950
Italy 15 695
Spain 15 1690
Thailand 14 1074
Japan 9 592
France 8 651
Argentina 7 2568
Russia 7 327
Belgium 5 2302
Chile 5 264
Greece 5 187
Indonesia 5 518
Pakistan 4 413
Saudi Arabia 4 349
Switzerland 4 190
Vietnam 4 196
Austria 3 102
Israel 3 357
South Africa 3 129
Croatia 2 46
Cuba 2 73
Finland 2 202
South Korea 2 166
Bangladesh 1 225
Colombia 1 92
Malaysia 1 30
Mexico 1 14
New Zealand 1 55
Philippines 1 27
Poland 1 41
Portugal 1 268
Sweden 1 72
Taiwan 1 60
Tunisa 1 255
Ukraine 1 20
RCTs per country
RCTs per country (detail)
RCTs per country per decade
Children randomized per country per decade
Sample size over time
Sample size over time (showing all RCTs)

Searches and data extraction (in duplicate) were updated quarterly until 2022Q3. After that I’ve added trials I’ve become aware of and extracted a minimal dataset.

See https://dx.doi.org/10.1186/cc13083 for methods and more information and https://www.zotero.org/groups/1345589/picutrials/library for the full list of trials.

Please send me trials I’ve missed or full-texts I don’t have access to so I can add them. Contact Mark Duffett (duffett@hhsc.ca or mark.duffett@gmail.com) for more information.