Editing Randomized controlled trial (section)

=== Transport science ===

Researchers in transport science argue that public spending on programmes such as school travel plans could not be justified unless their efficacy is demonstrated by randomized controlled trials.<ref name="Rowland et al (2003)">{{Cite journal |vauthors=Rowland D, DiGuiseppi C, Gross M, Afolabi E, Roberts I |date=January 2003 |title=Randomised controlled trial of site specific advice on school travel patterns |journal=Archives of Disease in Childhood |volume=88 |issue=1 |pages=8–11 |doi=10.1136/adc.88.1.8 |pmc=1719287 |pmid=12495948}}</ref>  Graham-Rowe and colleagues<ref name="Graham-Rowe et al (2011)">{{Cite journal |vauthors=Graham-Rowe E, Skippon S, Gardner B, Abraham C |year=2011 |title=Can we reduce car use and, if so, how? A review of available evidence. |journal=Transportation Research Part A: Policy and Practice |volume=44 |issue=5 |pages=401–418 |bibcode=2011TRPA...45..401G |doi=10.1016/j.tra.2011.02.001}}</ref>  reviewed 77 evaluations of transport interventions found in the literature, categorising them into 5 "quality levels".  They concluded that most of the studies were of low quality and advocated the use of randomized controlled trials wherever possible in future transport research.

Dr. Steve Melia<ref name="Melia 2011">{{Cite journal |vauthors=Melia S |date=2011 |title=Do Randomised Control Trials Offer a Solution to 'low Quality' Transport Research?' |url=http://eprints.uwe.ac.uk/16117/ |journal=Transportation Research Part A |location=Bristol |publisher=University of the West of England}}</ref> took issue with these conclusions, arguing that claims about the advantages of RCTs, in establishing causality and avoiding bias, have been exaggerated.  He proposed the following eight criteria for the use of RCTs in contexts where interventions must change human behaviour to be effective:

The intervention:

# Has not been applied to all members of a unique group of people (e.g. the population of a whole country, all employees of a unique organisation etc.)
# Is applied in a context or setting similar to that which applies to the control group
# Can be isolated from other activities—and the purpose of the study is to assess this isolated effect
# Has a short timescale between its implementation and maturity of its effects

And the causal mechanisms:

# <li value="5">Are either known to the researchers, or else all possible alternatives can be tested
# Do not involve significant feedback mechanisms between the intervention group and external environments
# Have a stable and predictable relationship to exogenous factors
# Would act in the same way if the control group and intervention group were reversed