1. School Major Setting: Yale University has not set up the major of world urban planning, which is relatively new and has not yet established a high reputation and influence in the world.
2. Research strength and faculty: The ranking of world urban planning majors will consider the research strength and faculty of the school. Yale University's research strength and faculty in the field of urban planning are relatively weak, which will affect its position in the rankings.
3. School reputation and influence: The ranking will also consider the overall reputation and influence of the school. Yale University is well-known and influential in other fields, and relatively low in the field of urban planning, which leads to its low position in the rankings.