Avoidance
In the general case, selection biases cannot be overcome with statistical analysis of existing data alone, though Heckman correction may be used in special cases. An informal assessment of the degree of selection bias can be made by examining correlations between exogenous (background) variables and a treatment indicator. However, in regression models, it is correlation between unobserved determinants of the outcome and unobserved determinants of selection into the sample which bias estimates, and this correlation between unobservables cannot be directly assessed by the observed determinants of treatment.
Read more about this topic: Selection Bias
Famous quotes containing the word avoidance:
“Tax avoidance means that you hire a $250,000-fee lawyer, and he changes the word ‘evasion’ into the word ‘avoidance.’”
—Franklin D. Roosevelt (1882–1945)
“The American Dream, the idea of the happy ending, is an avoidance of responsibility and commitment.”
—Jill Robinson (b. 1936)
“Real good breeding, as the people have it here, is one of the finest things now going in the world. The careful avoidance of all discussion, the swift hopping from topic to topic, does not agree with me; but the graceful style they do it with is beyond that of minuets!”
—Thomas Carlyle (1795–1881)