Nowadays, many organizations have innovative workplaces with desk-sharing and desk-rotation. The main objectives are 1) to improve organizational performance by better communication, and 2) cost reduction by the more efficient use of accommodation and other facilities. Although some research has been conducted into the use and experience of new offices, there is a need for sound data about the overall effects on organizational performance and user needs. Commissioned by the government, the Center for People and Buildings in Delft has developed an instrument for an ex ante or ex post evaluation of non-territorial offices. The tool has been based on an extensive literature review and is being tested in a number of case studies. The tool can be used to indicate problems in the present situation, to evaluate the effects of design interventions, and in support of decisions to change the physical working environment.