"Almost all firms in developing countries have fewer than ten workers, with a modal size of one. Are there potential high-growth entrepreneurs, and can public policy help identify them and facilitate their growth? A large-scale national business plan competition in Nigeria provides evidence on these questions. Random assignment of US$34 million in grants provided each winner with approximately US$50,000. Surveys tracking applicants over five years show that winning leads to greater firm entry, more survival, higher profits and sales, and higher employment, including increases of over 20 percentage points in the likelihood of a firm having ten or more workers."

"We document the presence of multiple and varied constraints to small and medium firm growth. This presents both a practical problem for business training programs and a challenge to academic economists trying to identify mechanisms through which these programs may affect outcomes. External validity needs theory. This pushes researchers to narrowly defined and highly selected sample frames, which limits the potential for clear, generalizable policy prescriptions. Ultimately, larger samples, multi-arm evaluations, process documentation, and narrowly-focused, theory-supported empirical work are all needed, but the complexity of the problem limits what we learn from any single study."