Final answer:
The clearance model of ethnic neighborhood change is when outmigration decreases a community's population to a point where it's hard to sustain the group's cultural identity.
Step-by-step explanation:
The clearance model of ethnic neighborhood change characterizes change when large numbers of the host group move away from their ethnic region or homeland, which may degrade the numbers needed to sustain the group's cultural identity. This can lead to the dilution or even the disappearance of the ethnic characteristics that once defined the neighborhood. In contrast, geography might play a role in preserving ethnic identity if the location is inaccessible to outsiders, thereby maintaining the cultural uniqueness of an area, as seen with the Cajun and Creole communities. However, economic forces, such as outmigration for job opportunities and incoming populations, can contribute to the clearance process, potentially threatening the survival of ethnic identities over time.