A/RES/71/177 Rights of the child mobility of people, including through the implementation of planned and well managed migration policies; (d) Expresses serious concern about the situation of vulnerability and risk faced by migrants in transit and destination countries, in particular migrant children, including adolescents, who are unaccompanied or separated from their families, who are forced to flee or decide to leave their homelands owing to multip le causes, and calls upon States of origin, transit and destination to work together to find effective and sustainable solutions, including within a framework of solidarity and regional and international cooperation; (e) Emphasizes the need for reliable statistical data disaggregated by sex, age and migratory status on international migration, including on migrant children, and in that regard calls upon the United Nations system and other relevant international organizations and multilateral institutions to enhance their cooperation in the development of methodologies for the collection and processing of statistical data on international migration and the situation of migrant children in countries of origin, transit and destination and to assist Member States in their capacity-building efforts in this regard; (f) Recognizes all efforts made by Governments, all relevant bodies, agencies, funds and programmes of the United Nations system, other relevant intergovernmental, regional and subregional organizations, including the International Organization for Migration and other organizations of the Global Migration Group, and non-governmental stakeholders, including the private sector, in addressing international migration and development for the benefit of bot h migrants and societies, and bearing this goal in mind emphasizes the need to strengthen partnerships among all relevant stakeholders; (g) Requests all States, international and national organizations and relevant stakeholders to take into account in their policies and initiatives on migration issues the global character of the migratory phenomenon and to give due consideration to international, regional and bilateral cooperation in this field, including by undertaking dialogues on migration that include countries of origin, transit and destination, as well as civil society, including migrants, with a view to addressing, in a comprehensive manner, inter alia, its causes and consequences and the challenge of unaccompanied children and irregular migration, granting priority to the protection of the human rights of migrants; IV Follow-up 88. Recalls its resolution 69/157 of 18 December 2014, in which it invited the Secretary-General to commission an in-depth global study on children deprived of liberty, to be funded through voluntary contributions, in this regard encourages Member States and United Nations agencies, funds, programmes and offices, as well as other relevant stakeholders, to support the elaboratio n of the study, and invites the designated independent expert who will lead the study to update Member States on the progress made and to submit a final report to the General Assembly at its seventy-third session; 89. Decides: (a) To request the Secretary-General to submit to the General Assembly at its seventy-second session a report on the rights of the child containing information on 18/19