Measuring changes to poverty levels over time

Hello Rahul - Thanks for your feedback. Our experience is that indicators which are most sensitive to changes in poverty for the ultra-poor are often not the easiest for enumerators to verify. That is a trade-off which we constantly need to manage as we determine which indicators should be included in the tool. Our PPIs are built using a country's National Poverty Lines. Indicators in a PPI are therefore chosen such that they are most relevant to households whose per-capita /per-adult-equivalent daily consumption expenditure is "around" this line. We are however in the process of making a change to the PPI's methodology which we believe will enhance its ability to predict poverty (both at a point in time and over time), at lines lower or higher than this one. Response options for the same indicators will be allotted different points depending upon the poverty line that you plan to use. This is because the level of association of an indicator to poverty may not be the same across all poverty lines. What our change will mean in practice is that the "weight" of an indicator to the final PPI score will vary depending on the poverty line used. Our paper on the PPI's new methodology will be released later this year. We will also provide users with detailed advice on what this means in terms of changes to the way they are currently administering the PPI. Please stay tuned. Also, we intend to add an additional "lower" 2011 PPP poverty line - the $1.00/day line to all PPIs going forward.