Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Psoriasis severity
Systematic review	People with psoriasis (severity not reported), number of people in analysis not reported 5 RCTs in this analysis	Psoriasis severity scores 4–12 weeks with vitamin D derivatives with dithranol short-contact therapy	SMD –0.44 95% CI –0.72 to –0.16	Effect size not calculated	vitamin D derivatives
RCT	171 people with chronic plaque psoriasis covering 10% of body surface or less (baseline severity scores: 6.3 with calcipotriol group v 6.2 with dithranol group)	ESI score (9-point scale) 8 weeks 2.6 with calcipotriol 3.8 with dithranol	P = 0.0001 for comparison of change in score	Effect size not calculated	calcipotriol