epidemiology studies have demonstrated inconsistent associations between type 2 diabetes mellitus and the risk of malignant melanoma. to this end, the aim was to perform a meta-analysis of cohort studies.medline, pubmed, embase and the cochrane library were searched up to february 2014. cohort studies addressing the relative risk of type 2 diabetes mellitus on malignant melanoma were included i...

This note develops a simple occupational choice model to examine three types of selection biases that may occur in empirically estimating the premium for uncertain wages. Individuals may select themselves into risky (wage-uncertain) jobs because they have (1) lower risk aversion, or (2) lower income risks, or (3) higher individual ability. We show that (1) gives no bias, (2) biases the OLS esti...

while ignoring income distribution and estimating aggregate demand generally leads to aggregation bias and thus, does not reflect households’ demand properly, yet aggregation bias is rarely considered in empirical demand studies and simply is ignored in most cases. the objective of the present study is to estimate aggregation bias in households’ demand for various types of meats and to evaluate...

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Background: Confounding can be thought of as mixing the effect of exposure on the risk of disease with a third factor which distorts the measure of association such as risk ratio or odds ratio. This bias arises because of complex functional relationship of confounder with both exposure and disease (outcome). In this article, we provided a conceptual framework review of confounding issues in epi...