Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
Do middle-income countries face difficult challenges producing consistent growth? Using transition matrix analysis, we can easily reject any unconditional notion of a “middle-income trap” in the data. However, countries have different fundamentals and policies. Using a non-parametric classification technique, we search for variables that separate fast- and slow-growing countries. For middle-income countries, a relatively large working age population, sex ratio imbalance, macroeconomic stability, and financial development appear to be the key discriminatory variables. We do the same exercise for low-income countries. This framework yields conditions under which countries in the low- and middle-income ranges move forward or backward, or are trapped.