“…Launched in 1950, the Labor Insurance program covered workers of government-run enterprises, private company employees, blue-collar employees, and members of professional unions between the ages of 15 and 60. use health care, and selecting health insurance programs, studies that use cross-section data can only observe associative relationships Short and Lair, 1994;Roetzheim et al, 2000;Winter et al, 1993;Hsia et al, 2000;Merrill, 2001;Wu et al, 2001;Walters, 1999;McWilliams et al, 2004). Although advances have been made in estimation methods in an attempt to reduce biases inherent in observational and cross-sectional data, many studies, as pointed out by Levy and Meltzer (2004), failed to provide solid evidence on the causal effects of health insurance on access to health care and health status.…”