Rosenhan then did a follow-on study where he informed his own hospital that he would be sending pseudopatients into the hospitals, trying to get admitted.
Over the next 3 months, the staff were given questionnaires for every new patient who were admitted to the hospital 1-2 meant they were highly suspicious the patient was a pseudopatient and 9-10 meant they thought the patient was actually ill.
The trick of this study was that Rosenhan actually sent no pseudopatients in!
It was found that many patients were actually rated as 'pseudopatients' when all patients that were admitted were actually seeking help.
The results of the study turned out to be of the 193 patients who were admitted 41 were rated as pseudopatients by at least one member of staff. 23 were rated as pseudopatients by at least one psychiatrist and 19 were rated as pseudopatients by a psychiatrist and a member of staff!