{'fraction_non_alphanumeric': 0.032679738562091505, 'fraction_numerical': 0.018300653594771243, 'mean_word_length': 6.092592592592593, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Influence of design characteristics on the outcome of retrospective cohort studies.

SIR,-Swaen and Meijers (1988;45:624-9) present interesting data in which they relate investigator orientated variables (country, journal, authors' affiliation, and financiers) and study design characteristics to the outcome (positive/negative) of retrospective cohort studies. Their data show that 76% of studies examined that were conducted by epidemiologists employed by governmental agencies were positive, compared with 36% of those conducted by epidemiologists employed by industry. Most negative studies were reported in the chemical industry. Several possible explanations for the proportions observed are related to the methodological limitations of the authors' approach.