Samar et al. investigate differences in relevance assessments given to documents from the open Web and ClueWeb12, including overlapping documents, and find that documents from the open Web are generally assigned higher relevance scores by assessors. They further identify a sample of ClueWeb12 documents that can potentially enhance the representativeness of techniques developed by researchers using the collection and propose a method that can be used to identify additional documents from ClueWeb12 in the future that allow for the development of more representative retrieval techniques.