Establishing panel studies – long-term studies where a cross-sectional sample of units is selected and surveyed at regular intervals – is difficult in developing countries. This difficulty is due to the absence of the long-term surveillance systems usually found in developed countries. Studies in developing countries need to be carefully designed to ensure that all necessary information is captured at the outset. Data must be maintained in a format suitable for long-term analysis. The initial study is particularly important.

The period of 1800 to 1950 saw dramatic changes in the economy and standards of living in Britain, resulting in the development of social policy and the creation of the welfare state. Child welfare became a central concern and, by the end of this period, a rigorously defined and more universal notion of the child and the nature of childhood had emerged. The distinct status of the child was itself partly created through the operation of social policy.

 In the developed world the importance of evidence-based policy is increasingly recognised. Panel studies – a long-term study design where a cross-sectional sample of units is selected and surveyed at regular intervals – are being used to gather information about the same people or communities over a number of years. Panel studies distinguish between transitory and persistent states and help explain relationships between variables, such as health, age, and education. They are, however, complex and costly to undertake.

Social capital has been defined in numerous ways, and can refer to sociability, social networks and support, trust, reciprocity and community and civic engagement. The effect of social capital upon children's well-being is under-researched, and adults' social capital is often used as a proxy for children's social capital. This fact is only slowly being recognised, there is a need to develop research on measuring children's social capital.

 Health research in developing countries has thus far produced few group studies. This is due to the cost and technical challenges of conducting research and limited capacity to implement research-driven recommendations. Measures of poverty are rarely applied in a child-centric fashion and have solely focused on income. Increasingly, however, poverty is being recognised as encompassing low achievement in education and health, vulnerability and exposure to risk.