The dataset was created on the 2002 ward level data, by comparison with the 2012 ward data. We recommend caution when comparing ward level data of 2012 with those of 2002 as there are uncertainties in the merging of the 2012 ward level boundaries with those from 2002, especially in urban areas.
For more information, please contact: Rob Swinkles (rswinkels@worldbank.org)