An Executable Concept Slice extracts from a program an executable subprogram that captures the semantics of a specified high-level concept from the program. Executable concept slicing combines the executability of program slicing, with the expressive domain level criteria of concept assignment. This paper presents results from an investigation of executable concept slice size to assess the effectiveness of executable concept slicing. The results show that the coherence of concept-based slicing criteria allows them to produce smaller executable concept slices than arbitrary criteria, providing evidence for the applicability of Executable Concept Slicing.