Halstead Difficulty is a metric used to estimate the difficulty of a software program based on its complexity. It is derived from the Halstead metrics, which analyze various aspects of the code, such as the number of operators and operands. The formula combines these elements to provide a numerical value that indicates how challenging the code may be to understand and maintain. This difficulty measure helps developers and project managers assess the potential risks associated with a software project. A higher Halstead Difficulty score suggests that the code may require more effort to comprehend, which can impact development time and resource allocation.