Publications [#224102] of Amar Hamoudi

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Papers Accepted

  1. Hamoudi, Amar and Jennifer Beam Dowd. "'Light from a Distant Star': Lagged selection bias and artifactual trends in mortality." International Journal of Epidemiology  (May, 2014).
    (last updated on 2014/07/21)

    Abstract:
    Recent public health studies have made headlines by reporting that for some disadvantaged U.S. subpopulations, mortality rates are higher and life expectancy lower today than in the past. In misleading syntax, this pattern has been described as a “fall” or “decline” in life expectancy. We illustrate how this important syntactic choice is akin to comparing average temperatures for the entire U.S in 1990 to only those for Alaska in 2010, and describing the difference as a “decline.” We argue that it is long past time to examine an alternative—and arguably more plausible—interpretation of these patterns. We explicate dynamics underlying what we call “Lagged Selection Bias” (LSB). Drawing on a real-world example, we illustrate why comparing the same measure at two points in time in the presence of LSB does not actually identify a trend. Specifically, if there are large and stable social disparities in health, life expectancy in a more disadvantaged group can be lower in 2010 than in 1990-- even though everyone lives longer in the later period. We urge greater caution for researchers interpreting changes in period measures stratified by subgroups whose composition is changing, and discuss approaches to managing the problem.

Amar Hamoudi