Correction to: Trials

https://doi.org/10.1186/s13063-018-2614-7

After publication of our article [1] we became aware that several sections of text in our Methods section were copied from a previously published article [2]. We would like to formally apologize and give credit to the authors of that article [2]: Chris Smith, Uk Vannak, Ly Sokhey, Thoai D Ngo, Judy Gold, Khemrin Khut, Phil Edwards, Tung Rathavy and Caroline Free.