['24', '25', '11417', 'Likewise,', 'the', 'subjects', 'in', 'Emmons', 'et', 'al.', '"were', 'volunteers', 'who', 'responded', 'to', 'advertisements', 'for', 'a', 'study', 'on', 'passive', 'smoking."', 'Also,', 'the', 'Emmons', 'et', 'al.', 'subjects', 'were', 'selected', 'to', 'yield', 'a', 'wide', 'range', 'of', 'ETS', 'exposures,', 'not', 'necessarily', 'to', 'be', 'representative.', 'In', 'fact,', '106', 'of', 'the', '186', 'subjects', 'represent', 'just', 'nine', 'different', 'work', 'sites.', 'In', 'no', 'way', 'can', 'the', 'reported', 'prevalence', 'or', 'magnitude', 'of', 'ETS', 'exposure', 'annem', 'these', 'study', 'participants', 'be', 'generalized', 'to', 'the', 'entire', 'non-smoking', 'U.S.', 'workforce.', 'Given', 'the', 'nature', 'of', 'recruitment', 'in', 'both', 'studies,', 'it', 'is', 'surprising', 'that', 'even', 'larger', 'percentages', 'did', 'not', 'report', 'ETS', 'exposure.', 'Think', 'about', 'this.', 'Why', 'would', 'people', 'volunteer', 'to', 'participate', 'in', 'a', 'study', 'on', 'driving', 'habits', 'if', 'the', 'didn’t', '.', "'", 'drive?', 'Now', 'think', 'about', 'this.', 'Why', 'would', 'people', 'volunteer', 'to', 'participate', 'in', 'a', 'study', 'on', 'ETS', 'exposure', 'if', 'they', 'did', 'not', 'believe', 'they', 'were', 'ETS', 'exposed?', 'The', 'fact', 'that', 'these', 'two', 'studies', 'are', 'not', 'representative', 'is', 'no', 'secret.', 'In', 'their', 'paper,', 'Cummings', 'et', 'al.', 'plainly', 'state', 'that,', '"Given', 'the', 'self-selected', 'nature', 'of', 'the', 'study', 'population', 'and', 'potentially', 'limited', 'generalizability', 'of', 'results', '....”', 'Likewise,', 'Emmons', 'et', 'al.', 'describe', 'their', 'study', 'population', 'as', '"a', 'motivated', 'sample', 'of', 'convenience"', 'ESLC', 'I9PLTS', 'BAYLEY', 'REPORTING,', 'INC.', '(202)', '234-7787', '(800)', '368-8993', ' ']