All licensed Structural Engineers (S.E.s) are also licensed Professional Engineers (P.E.s). All Professional Engineers, however, are not licensed Structural Engineers. In fact, only a small fraction of Professional Engineers go on to pass the State requirements that allow Professional Engineers to be licensed Structural Engineers.
A practicing engineer is initially required to pass an examination to be conferred the title of Professional Engineer. This is a title that allows the engineer to practice in the varied branches of Civil Engineering such as Structural Engineering, Transportation Engineering, and Geotechnical Engineering to name a few. Only after serving an additional four year apprenticeship under a licensed Structural Engineer, and passing a much more rigorous series of examinations for the state licensing board, is a Professional Engineer conferred the title of Structural Engineer.
A good analogy that serves to illustrate the difference between a P.E. and an S.E. is that of a medical General Practitioner versus a specialist such as a Cardiologist. While a General Practitioner could see a patient for a heart problem, one would likely prefer to be seen by a Cardiologist. Much the same relationship exists in the engineering field.
In addition, the experience we have gained providing litigation support has shown us that when a project or evaluation is brought into question and the engineer who performed it is a Professional Engineer and not a Structural Engineer, the party who retained the engineer has opened themselves to scrutiny. Again using the medical analogy, it is much less likely for the Cardiologist to make a mistaken diagnosis as it relates to a heart condition than a General Practitioner – and if a mistake is made, at least the decision by the client cannot be brought into question since they did rely on the appropriate expert for the field.