Clusters are geographic concentrations of industries related by knowledge, skills, inputs, demand, and/or other linkages. A growing body of empirical literature has shown the positive impact of clusters on regional and industry performance, including job creation, patenting, and new business...

We organized business associations for the owner-managers of randomly selected young Chinese firms to study the effect of business networks on firm performance. We randomized 2,800 firms into small groups whose managers held monthly meetings for one year, and into a "no- meetings" control group....

Management has a large effect on the productivity of large firms. But does management matter in micro and small firms, where the majority of the labor force in developing countries works? We develop 26 questions that measure business practices in marketing, stock-keeping, record-keeping, and...

Although a large literature seeks to explain the "missing middle" of mid-sized firms in developing countries, there is surprisingly little empirical backing for existence of the missing middle. Using microdata on the full distribution of both formal and informal sector manufacturing firms in...

We provide a quantitative evaluation of the aggregate and distributional impact of microfinance or credit programs targeted toward small businesses. We find that the redistributive impact of microfinance is stronger in general equilibrium than in partial equilibrium, but the impact on aggregate...

We analyze different disability policy strategies using policy scores developed by the OECD for the period 1990 to 2007. Applying model-based and hierarchical agglomerative clustering, we investigate the existence of distinct country clusters, characterized by particular policy combinations. In...

It is standard practice in empirical work to allow for clustering in the error covariance matrix if the explanatory variables of interest vary at a more aggregate level than the units of observation. Often, however, the structure of the error covariance matrix is more complex, with correlations...

In empirical work in economics it is common to report standard errors that account for clustering of units. Typically, the motivation given for the clustering adjustments is that unobserved components in outcomes for units within clusters are correlated. However, because correlation may occur...

Tech clusters like Silicon Valley play a central role for modern innovation, business competitiveness, and economic performance. This paper reviews what constitutes a tech cluster, how they function internally, and the degree to which policy makers can purposefully foster them. We describe the...