Barton Associates Inc. | 19,093 followers on LinkedIn. The Locum Tenens Experts | Welcome to Barton Associates, the locum tenens staffing and recruiting experts. Founded in 2001, Barton Associates is a leading national locum tenens physician, dentist, nurse practitioner, and physician assistant staffing and recruiting firm. With more than 800 employees and 10 offices (and more on the horizon), Barton Associates has the experience, resources, and scale needed to efficiently match talented locum tenens providers in many different specialties with great healthcare facilities and practices across the United States in a wide variety of practice areas.