Social isolation and death alone in the prefabricated temporary housing after a disaster has been a social concern. The importance of social ties among the community has been suggested and several reports pointed out the positive effect of “group allocation” which preserves pre-existing local social ties compared to the “lottery allocation”.

Japan Red Cross Society recommended “group allocation” as a better option than “lottery allocation” on their guidelines. However, many municipalities carried out “lottery allocation” for temporary housing arrangement after the Great East Japan Earthquake (GEJE).

To collect the information about the accelerating factors and bottlenecks when practicing the “group allocation”.

In-depth interview was conducted between August and November 2013. Interviewees were the professionals of disaster management, individuals who were involved in arranging the prefabricated housing and the residents. This research was supported by the Ministry of Education, Culture, Sports, Science, and Technology in Japan.

This study found the municipality which carried out “group allocation” had characteristics such as: (1.) the staff in charge of housing arrangement had the information about the positive effect of “group allocation”, and (2.) pre-existing community leaders were able to gather residents’ opinions, and citizens were involved in the decision making to some content.

Although this study is based on the experience of a limited number of key persons, it would be useful to give the insight about the possible bottleneck for the practitioners who will be in charge of housing arrangement under the disaster setting in future. Also, the relevancy and evidence about “group allocation” should be carefully examined in the context of preventing social isolation as well as various long-term effects. It would be essential that the knowledge and experience will be accumulated and shared between municipalities in a usable and comparable format.