Investopedia contributors come from a range of backgrounds, and over 25 years there have been thousands of expert writers and editors who have contributed. Erika Rasure is globally-recognized as a ...

Doretha Clemons, Ph.D., MBA, PMP, has been a corporate IT executive and professor for 34 years. She is an adjunct professor at Connecticut State Colleges & Universities, Maryville University, and ...

Control theory is a branch of mathematics and engineering, which defines the conditions needed for a system to maintain a controlled output in the face of input variation. Classically developed for ...