The con‡ict in Darfur has been described both as an ethnic cleansing campaign, carried out by the Sudanese government and its allied militias, and as a local struggle over dwindling natural resources between African farmers and Arab herders. In this paper, we construct a theoretical framework...

We highlight the fact that the Sargan-Hansen test for GMM estimators applied to panel data is a joint test of valid orthogonality conditions and coefficient stability over time. A possible reason why the null hypothesis of valid orthogonality conditions is rejected is therefore that the slope...

Product selection matters for a firm’s productivity and long-run growth. Recent theoretical and empirical studies indicate that an important margin of adjustment to policy reforms is the reallocation of output within firms through changes in product mix decisions. This paper examines the...

bel and Eberly (1999) show that the effect of uncertainty on long run capital accumulation is ambiguous in a real options model with irreversible investment. We show that a higher level of uncertainty tends to reduce expected capital stock levels in a model with strictly convex adjustment costs....

We study the sensitivity of investment to cash flow conditional on measures of q in an adjustment costs framework with costly external …nance. We present a benchmark model in which this conditional investment-cash flow sensitivity increases monotonically with the cost premium for external …-...