2 Progress and challenges in data availability and quality The SDG target of a legal identity for all, including birth registration, by 2030 is measured by indicator 16.9.1: the proportion of children under 5 years of age whose births have been registered with a civil authority. The primary sources for such data are vital statistics drawn from civil registration systems, national censuses and household surveys, including those implemented as part of international survey programmes such as the Demographic and Health Surveys (DHS) and Multiple Indicator Cluster Surveys (MICS). Functioning civil registration systems are the main vehicles through which a legal identity for all – and SDG target 16.9 – can be achieved. Civil registration systems that are operating effectively compile vital statistics that are used to compare the estimated total number of births in a country with the absolute number of registered births during a given period. However, the systematic recording of births in many countries remains a serious challenge, highlighting the urgent need to improve and strengthen civil registration and vital statistics. 12 Birth Registration for Every Child by 2030: Are we on track? A recent UNICEF review of 14 countries found a wide range of progress in this area.24 While most countries had strategic plans to improve civil registration systems, persistent gaps and challenges remained. They included: insufficient legal frameworks to support the production of vital statistics, prohibitive fees for registration, complex and cumbersome processes for late registration, limited resources (both financial and human), underdeveloped quality assurance mechanisms, persistent barriers to access, and lack of completeness of records, limiting the accuracy and reliability of vital statistics. While data coverage has improved over time, this has largely been the result of investment in collecting data on birth registration in low- and middle-income countries through household surveys. In fact, in the absence of reliable administrative records, household surveys have become a key source of data to monitor levels and trends in birth registration.