Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Adverse effects
RCT	113 people with mild to moderate psoriasis	Proportion of people with grade 2 erythema 56% with twice-weekly UVB 31% with 3 times-weekly UVB Absolute numbers not reported	P = 0.007	Effect size not calculated	twice-weekly UVB