This study carried out a literature review to understand better how ATCO teams co-ordinate and share information. This is an important baseline to establish prior to embarking or considering other staffing options such as Multi Sector Planning (MSP), Single Person Operations (SPO) or removing or automating a task. This report describes teamwork / team co-ordination aspects based on the findings from literature relevant when considering changing staffing options. In addition, a framework is proposed to guide the assessment of the expected impact on teamwork when considering different staffing options. The scope of the current framework is limited in its application to the en-route environment. For the purpose of this study, the focus has been predominantly on the ™standard™ sector team i.e. consisting of Planning Controller (PC) and Tactical Controller (TC).