The interview process began with a 30min recruiter screening interview. Next was a 1 hr interview with a more sr. recruiter. If the process continued, the next interview would be with an actual ghSmart consultant, who would administer an assessment (like the firm does for clients). This is well described in Geoff Smart's books and on their website as other reviewers have mentioned. They bring candidates through the process in cohorts every couple months based on hiring needs. This did make the series of interviews a bit slower and uncertain as they were cutting candidates / running a process in the background. I rated the interviews as difficult, as the process is different from other interviews, and so you want to prep accordingly.