<Li> In Philippines, due to a centralized government and almost unequal distribution of government power and funds, people from the provinces head to Metro Manila to look for better jobs and opportunities . This has been continuing since then, although in much smaller numbers now, with Metro Cebu and Metro Davao now increasingly becoming more popular as alternative destination for internal migrants . </Li> <Li> In Italy, during the country's economic miracle in the 1950s and 1960s, the so called "Industrial triangle" of Northwest Italy experienced waves of immigrants coming from Southern Italy, due to the southern portion of the country remaining underdeveloped and stricken with poverty . The peak was reached between 1955 and 1963, when as much as 1,300,000 southern workers moved to the northern industrial cities . After a pause in the 1980s the north - south migration has resumed, this time headed to other areas of the north and Central Italy . </Li> <P> A subtype of internal migration is the migration of immigrant groups--often called secondary or onward migration . Secondary migration is also used to refer to the migration of immigrants within the European Union . </P> <P> In the United States, the Office of Refugee Resettlement, a program of the U.S. Department of Health and Human Services's Administration for Children and Families, is tasked with managing the secondary migration of resettled refugees . However, there is little information on secondary migration and associated programmatic structural changes . Secondary migration has been hypothesized as one of the driving forces behind the distribution of resettled refugees in the United States . </P>

Explain three causes of internal migration shifts in the united states during modern times