{'fraction_non_alphanumeric': 0.013157894736842105, 'fraction_numerical': 0.0, 'mean_word_length': 5.2272727272727275, '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}}
[Errors of measurement and epidemiology].

The quantification of measurement errors is rarely considered during the preparation of a study protocol in epidemiology. This is in contradiction with the impact of these errors on the assessment of degree of association between various measures, which is often the objective of these protocols. A few important definitions of measurement errors are first proposed. The impact of these errors on the assessment of measures of central tendency and association is studied through examples and simple simulations. These measures must be exact since they play such an important role in estimating risk factors or in evaluating diagnostic tests.