At least he's got some credible material to work with: Ford vehicles have performed well in independent quality and reliability studies.

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This disparity has led to questions about the reliability of twins studies.

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There are other types of analyses that fall between observational studies and the best clinical trials in their reliability.

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The reliance on self-reporting weight, height, activity, and soda consumption in some studies rather than independent measuring and verification might confound their reliability, as might small sample sizes.

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