This is the first Ideas42 impact report. It assesses the way in which a decade of behavioral interventions in finance, justice, the environment, education, health and poverty have positively affected the lives of people. It provides summaries of 40 projects in the first 10 years of intervention, many of which are still ongoing. Outstanding in the pensions area is the project for helping more Mexican nationals to save for a secure retirement, combat high poverty rates among the elderly and encourage voluntary pension contributions. 20 million Mexicans now receive statements designed by Ideas42.