This chapter investigates measure to how severe the poverty problem is according to each of them. It aims to answer how and to what extent the picture of poverty will change when measurement methods are changed. The chapter presents an overview of the basic approaches to poverty research and the applied methods, and examines the strengths and weaknesses of each approach. It describes the extension of poverty and analyses the pictures created by die different measures. Other data-bases measure annual income and therefore more enduring poverty, but information on different forms of short-term poverty may be lost. The demands of political relevance have been a major motivation for the increased pursuit of establishing poverty criteria on the basis of public opinion. Information on the duration of poverty is based on survey-type panel data since no statistical information is available.