The phrase "great heterogeneity" means that there is a wide variety or diversity within a particular group or category. It suggests that there are many differences or variations among the things or people being discussed. Full definition
«But I think there is still great heterogeneity in practice in the U.S.» (sciencenews.org)
Dots above the diagonal represent patients with larger heterogeneity in the primary tumors; dots below the diagonal represent greater heterogeneity in the metastatic tumors while the central diagonal grey line represents identical heterogeneity between the two types of tumors. (jcancer.org)
Forest management practices favouring natural regeneration can result in greater heterogeneity and complexity of forests, which may be desirable for some purposes, but at the same time makes forest monitoring and management more difficult. (sciencedaily.com)