I am not an economist: formally, I studied philosophy, ancient history and literature, then experimental psychology. I have attempted to understand the reasoning in Dr Ravallion's and Dr Chen's methodology papers underlying statements on global poverty since 1981, and the reasoning behind Dr Ravallion's proposals for the future. The purpose of this comment is to ask how the likely extent of the potential problems below is known to or inferred by macroeconomists to be small, or alternatively how the uncertainties about them are taken into account. To the points in the email below I add two more: 1. Since the FAO adjust for rising food needs per person due to rising adult-child ratios, it is not clear why the World Bank does not do likewise. Other things being equal there would be an element of spurious progress. 2. It is not clear why the Bank has not factored in numbers of AIDS deaths, especially in sub-Saharan Africa, into an assessment of the progress of poor people since 1981. I am unaware of anyone other than myself who raised this seriously as a general problem for international goal setting or economic theory - that macroeconomic figures look better if some people die - in the roughly two decades between the discovery of AIDS and the Millennium Declaration of 2000. Following my raising the problem with Professor Morduch, then of Princeton, his colleague Angus Deaton raised it as a serious issue in a paper of December 2000 commissioned by the Chief Economist of the World Bank on how to monitor progress for MDG1. I subsequently explained the problem to, among others, Professors Sachs and Kanbur, three senior employees at the World Bank, officials at the OECD and the UK Department of International Development, my member of Parliament and through him the UK's Governor of the World Bank Clare Short. Professor Sachs and Professor Kanbur, and the incoming Chief Economist of the World Bank Francois Bourguignon, later co-wrote papers based on this idea - that economists aggregating outcomes count those who die as well as those who stay alive. As I understand it, the papers have been accepted by other senior economists as important. This comment is to ask Dr Ravallion to clarify the two issues above and the four in the email below of 2007 for non-economists. Thank you. ............................. Email of 18 May 2007: Dear Dr Ravallion I am a member of the public with an interest in international development. I would be grateful for any comments you might have on the importance or otherwise of the following. I worked in Bangladesh in the mid-1980s, and lived with an illiterate family. A theme at the time was landlessness due to population rise: parents' land would be divided among several offspring. Apart from the general problem that income or spending do not directly measure assets, it seems to me that if people move to cities for work, they may begin paying rent, having previously lived on family land. It was not clear to me from Absolute Poverty Measures whether this kind of thing - changes in consumption needs - was taken into account, or whether the new urban/rural adjustments were solely for prices. Secondly, in respect of economies of scale, a plausible scenario might be that economic growth coincides with smaller household units, as single people travel to cities for work. This would be additional to considerations about economies of scale related to children's needs and smaller family sizes as birth rates fall. Thirdly and fourthly, it is not clear to me how surveys have generally dealt with expenditure on personal debt, or costs which are sometimes the subject of public concern and whose incidence varies across countries and times, such as charges for water, medicine or schooling. I would be grateful for any light you might be able to shed on these issues. Thank you. Yours sincerely, Matt Berkley.