Differing amounts of responsibility can be attributed to various design professionals working on a construction project.  The best way to determine the degree of individual responsibility is to examine their contact with the owner of the site.  The duties of a design professional can include routine checks to ensure that the progress being made is in compliance with plans and specifications, as well as conducting site inspections to observe adherence to code regulations; in addition to specific duties identified in their contract, design professionals are held to certain accepted standards while performing professional services, and must observe them throughout the process of construction.  Should they fail to meet the aforementioned standards, a design professional is at fault, and can be held liable if injury is suffered.