In a way, ecu, you have opened a topic that has been around for centuries, and to which there are innumerable answers.  However, we need to decide whether we are trying to define absolute or relative poverty.

Wikipedia explains absolute poverty thus:

Absolute poverty refers to a set standard which is consistent over time and between countries. The World Bank defines extreme poverty as living on less than US $1.25 (PPP) per day, and moderate poverty as less than $2 a day (but note that a person or family with access to subsistence resources, e.g. subsistence farmers, may have a low cash income without a correspondingly low standard of living - they are not living "on" their cash income but using it as a top up). It estimates that "in 2001, 1.1 billion people had consumption levels below $1 a day and 2.7 billion lived on less than $2 a day." A dollar a day, in nations that do not use the dollar as currency, does not translate to living a day on the amount of local currency as determined by the exchange rate. Rather, it is determined by the PPP - purchasing power parity, which would look at how much local currency is needed to buy the same things that a dollar could buy in the United States. Usually, this would translate to less local currency than the exchange rate in poorer countries as the United States is a more expensive country.

Relative poverty in the OECD and the European Union is based on "economic distance", a level of income set at 60% of the median household income.  It is really an index of income inequality, as opposed to 'poverty'.  The problem then is getting a valid and realistic income scale.  After all, whose job is more important to the overall health of the nation - a doctor, a bank manager or a dustman?