What is the test for having a property interest in a disability benefit?

"To have a property interest in a benefit, a person clearly must have more than an abstract need or desire for it. He must have more than a unilateral expectation of it. He must, instead, have a legitimate claim of entitlement to it. It is a purpose of the ancient institution of property to protect those claims upon which people rely in their daily lives, reliance that must not be arbitrarily undermined. It is a purpose of the constitutional right to a hearing to provide an opportunity for a person to vindicate those claims. Property interests, of course, are not created by the Constitution. Rather they are created and their dimensions are defined by existing rules or understandings that stem from an independent source such as state law-rules or understandings that secure certain benefits and that support claims of entitlement to those benefits." (Board of Regents v. Roth (1972) 408 U.S. 564, 577.)