Most large systems development efforts proceed in a top-down fashion where initialspecifications and requirements are incorporated into a high-level design, followed byprograms based on this design. However, a major part of the software life-cycle effort isdevoted to maintenance. While several...

Teachers differ greatly in how much they teach their students, but little is known about which teacher attributes account for this. We estimate the causal effect of teacher subject knowledge on student achievement using within-teacher within-student variation, exploiting a unique Peruvian...

Teachers differ greatly in how much they teach their students, but little is known about which teacher attributes account for this. We estimate the causal effect of teacher subject knowledge on student achievement using within-teacher within-student variation, exploiting a unique Peruvian...

I study a model where Information Technology, while typically increasing overall inequality, is likely to harm some people at intermediate and high levels of the distribution of income but to benefit people at the bottom. Within a given occupation it may harm some workers while benefitting...