00384    a2200097   4500082001800000100002200018245014200040260004000182300002600222650003800248  a362.50723 RVA  aRavallion, Martin  aPolicy Research Working Paper : The Mystery of the Vanishing Benefits Ms. Speedy Analyst's Introduction to Evaluation /cMartin Ravallion  aWashington :bThe World Bank,c1999  a40p. ;bill. ;c30 cm  aMystery of the Vanishing Benefits