An RCT was conducted in six European centres: London (UK), Ulm-Guenzburg (Germany), Rimini (Italy), Zurich (Switzerland), Groningen (the Netherlands) and Sofia (Bulgaria). Patients were included if they had a diagnosis of SMI (psychotic illness including bipolar disorder), were aged 18 to retirement age, had been ill and had major role dysfunction for at least two years, were living in the community at baseline, had not been in competitive employment in the preceding year and expressed the desire to enter competitive employment. They were randomly allocated to receive either IPS or the 'Vocational Service' (control service). Given the need to consider the impact of gender and work history on vocational outcomes (20), service allocation was stratified by centre, gender and work history (more or less than a month's competitive employment in the five years prior to baseline). Randomisation was conducted centrally using MINIM Version 1.5. A researcher at each centre recruited the patients, submitted them to the statistician for randomisation and received the allocation by email. The allocation sequence was concealed until the services had been assigned, but it was not possible for patients, professionals or researchers to be blind to service allocation thereafter.
