Abstract
This paper presents a novel concept based on the idea that each element of the initial universe has a possibility degree related to each element of the parameter set. It is an improved hybrid model that combines the key features of soft set, vague set and neutrosophic set, thus making it highly suitable for use in decision-making problems that involve uncertain and indeterminate data. Based on this new concept we define some related notions as well as some basic operations namely the complement, subset, equality, union, intersection, AND and OR along with illustrative examples. A similarity measure of two possibility neutrosophic vague soft sets is introduced and an application of this similarity measure in medical diagnosis is illustrated. Finally, a comparison between different existing methods and possibility neutrosophic vague soft set to show the ascendancy of our proposed method is provided.