This article responds to Graham-Rowe et al. (2011), which categorised 77 evaluations of transport interventions into 5 levels of ‘quality’. This article focuses on Graham-Rowe et al.’s treatment of randomised controlled trials (RCTs) and their recommendation, also made by others, that RCTs should be used ‘wherever possible’ in transport research. It analyses the RCTs reviewed by Graham-Rowe et al. and the hierarchy of research methods they use. It proposes 5 criteria for the valid application of RCTs, which it argues would imply that the circumstances in transport studies where RCTs are demonstrably superior to other methods are very limited. It finds no valid justification for a hierarchy of methods and argues that attempting to apply such a hierarchy would generate misleading advice for policy makers.
Melia, S. (2015, January). Do randomised control trials offer a solution to 'low quality' transport research?. Paper presented at 47th Annual UTSG Conference