Almas Heshmati Last year, a new study on green innovations and patents in 27 countries left one reader slack-jawed. The findings were no surprise. What was baffling was how the authors, two professors of economics in Europe, had pulled off the research in the first place. The reader, a PhD student in economics, was working with the same data described in the paper. He knew they were riddled with holes – sometimes big ones: For several countries, observations for some of the variables the study t...