Competitiveness varies between different types of programs as well as between different programs of the same type. For most institutions, admission to professional MS programs is less competitive than for PhD programs. There is a common perception of professional MS programs as income-generating programs that lack rigor that admit almost anyone who can pay the tuition. While it is true that professional MS programs are typically a source of revenue for their universities, programs at highly-ranked departments have rigorous admission standards. These standards will be different from those of a PhD program. Most notably, a common admission criterion for professional MS programs is whether the student has the necessary background and ability to be successful in the program, and whether the career goals of the student align with what the program can offer.
Admissions criteria and acceptance rates to academic MS programs can vary widely, and for a variety of reasons. Some programs are capacity-limited. Some programs at public universities have a mandate to prioritize serving the needs of in-state or domestic students. Some academic MS programs will preferentially accept candidates who they see as having the potential to successfully continue into their PhD program.