“…1 This negative result for what is perhaps the most natural regression model has long guided the search for solutions to the errors-in-variables problem towards approaches that rely on additional information (beyond x and y), such as instruments, repeated measurements, validation data, known measurement error distribution, etc (e.g., Hausman, Newey, Ichimura, and Powell (1991), Newey (2001), Schennach (2004a), Schennach (2004b), Schennach (2007), Hu and Schennach (2006), Hu and Ridder (2004), among many others). Nevertheless, since the seminal work of Geary (1942), a large number of authors (e.g.…”