Scrum of Scrums (SoS) is a scaled agile approach defined by Ken Schwaber in 2004 that refers to the meetings held with the upstream team in addition to the daily meetings of SoS' normal Scrum teams. SoS is a team formed by selecting one or two ambassadors from each Scrum Team when more than one Scrum Team needs to coordinate. The agenda items of the SoS meetings include what each team has accomplished since the last meeting, what each team will work on by the next meeting, risks, problems, and obstacles affecting other teams, and dependencies between the teams' work and their current status.