Dahl 2006b.

Methods	Randomised DBPC trial; multicentre
Participants	Adults 316 active (179 m); losses to f/u 42 318 placebo (193 m); losses to f/u 46
Interventions	12 months SLIT Sublingual tablet Grass pollen 75 000 SQ‐T Phl p 5 15 mcg Daily
Outcomes	Rhinoconjunctivitis symptom score Medication score Global assessment Adverse events
Notes	Jadad scale 5/5
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Low risk	The allocation sequence was generated by the sponsoring company and blinded for the investigators
Allocation concealment?	Low risk	Central allocation
Blinding? All outcomes	Low risk	Unblinded efficacy and safety assessments on subject level were available only for a biostatistician at the Contract Research Organization. All personnel associated with the study and participants remained blinded.
Incomplete outcome data addressed? All outcomes	Low risk	Outcome data were completed for each main outcome. Attrition and exclusions were reported. The numbers in each intervention group and reasons for attrition/exclusions were reported.
Free of selective reporting?	Low risk	The specified outcomes in the methodology were reported in the results section
Free of other bias?	Low risk	No other sources of bias were detected or suspected