http://www.time.com/time/nation/article/0,8599,1974927,00.htmlThe premise of using a biometric employment card (which would most likely contain fingerprint data) to stop illegal immigrants from working requires that all 150 million–plus American workers, not just immigrants, have one. Michael Cherry, president of identification-technology company Cherry Biometrics, says the accuracy of such large-scale biometric measuring hasn't been proved. "What study have we done?" he says. "We just have a few assumptions."