How to Define the Condition of an Infrastructure for Different Asset Management Purposes?

Many countries are implementing systems to assess the condition of their critical infrastructures. These systems serve as basis to take more informed and integrated decisions and to clarify priorities. Examples of these systems are different Asset Management Systems, the "Report Card for America\´s Infrastructure" in the USA and "The State of the Nation" project in England. In all of these systems a grade is given per infrastructure to express the general condition of the structure. The present paper aims to review the condition monitoring sources used in this process of assessment. Some of these sources are real technical measurements, and "estimations" informed by panels of experts. The initiatives of three countries; USA, England and Finland will be presented in the paper.