This book uses newly collected data with nearly 2000 observations across Africa and Latin America of SME owner/operators to examine if psychometric tools can distinguish the good ones from the bad ones. This book fully describes the development problem and how psychometric tools can help solve it. Moreover, it presents and develops the unique statistical methodologies to deploy psychometric tools for credit screening. This will be the single complete publication of the work to date by the entrepreneurial finance lab, created by Klinger & Khwaja. This work started as a research project at Harvard University's center for international development, with funding from Google.org. This work is very high profile, winning the G-20 SME Finance Challenge in 2010 (global open competition to identify the best scalable solutions to unlocking SME finance- winners honored at the G-20 summit in Seoul Korea and receiving significant funding from G-20 countries for the implementation of their models).