For several years now organizations are implementing innovative workplaces. Main objectives are an improvement of organizational performance and cost reduction by working more effectively and a more efficient use of accommodation and other facilities. Other objectives are: improving communication, attracting and retaining personnel and emitting a positive image. Although some research has been done already into the use and experience of new offices, there is a growing need for sound data collection about the effects of new concepts on organizational goals and user needs. Instructed by the Government, the Center for People and Buildings in Delft is developing an instrument that can be used for a diagnostic Pre- or Post-Occupancy Evaluation, including many relevant aspects. The tool can be used to evaluate the effects of design interventions, to indicate problems and to support decisions about changing the (physical) working environment. The instrument deals with the effect of the workplace on experience (satisfaction, health, image), use (behavioral patterns, occupancy), economical aspects (productivity, facility costs and Economic Value Added), future value (trends, adaptability to trends and organizational changes)) and the implementation process of new workplaces. It has a modular structure so users of the tool can select the subjects they want to include in a diagnosis. The introduction modules guide the user in choosing the scope of the evaluations, its objectives, research methods and prerequisites with respect to time and money, leading to an evaluation study that suits the conditions of the organization. Point of departure of the evaluation are the preliminary objectives set for the work environment and a clear description of the new and old situation (organization, working processes, facilities). The instrument provides a framework to analyze documents about the workplace, questions to execute interviews with ‘key-persons’ of the project organizations, questionnaires to ask the employees about their experiences, observations methods to list the use of the environment and a framework to check the costs and benefits. The modules of the instrument will be based on a review of literature and existing evaluation methods. Currently the instrument is being tested in cases at departments of the Dutch Government and other organizations. All data will be included in a database. As such, a number of data will become available for cross case research, building up a body of knowledge and benchmarking. The knowledge may fulfill our needs to confirm or disprove the hypotheses and expectations that go round in the field of facility management and real estate management.