On ecological fallacy, assessment errors stemming from misguided variable selection, and the effect of aggregation on the outcome of epidemiological study

Abstract

In social and environmental sciences, ecological fallacy is an incorrect assumption about an individual based on aggregate data for a group. In the present study, the validity of this assumption was tested using both individual estimates of exposure to air pollution and aggregate data for 1,492 schoolchildren living in the in vicinity of a major coal-fired power station in the Hadera region of Israel. In 1996 and 1999, the children underwent subsequent pulmonary function tests (PFT), and their parents completed a detailed questionnaire on their health status and housing conditions. The association between children's PFT results and their exposure to air pollution was investigated in two phases. During the first phase, PFT averages were compared with average levels of air pollution detected in townships, and small census areas in which the children reside. During the second phase, individual pollution estimates were compared with individual PFT results, and pattern detection techniques (Getis-Ord statistic) were used to investigate the spatial data structure. While different levels of areal data aggregation changed the results only marginally, the choice of indices measuring the children's PFT performance had a significant influence on the outcome of the analysis. As argued, differences between individual-level and group-level effects of exposure (i.e., ecological or cross-level bias) are not necessary outcomes of data aggregation, and that seemingly unexpected results may often stem from a misguided selection of variables chosen to measure health effects. The implications of the results of the analysis for epidemiological studies are discussed, and recommendations for public health policy are formulated.

Real-Time Associations Between Engaging in Leisure and Daily Health and Well-Being

“…Although not all examples of within-and between-person approaches produce seemingly "opposite" relationships (recall that they test separate questions and thus may either agree or disagree), this example highlights the ecological fallacy [17,18]. The ecological fallacy states that relationships between variables at one level (e.g., between individuals) cannot be assumed to exist at the same magnitude and direction at another level (e.g., within individuals) (for discussion of the different applications of between-and within-person models, see [19]).…”

Between-person and within-person approaches to the prediction of ambulatory blood pressure: the role of affective valence and intensity

“…These findings highlight the fact that relationships across levels-in this case at the between-person and within-person levels-do not always concur (Kramer, 1983;Portnov et al, 2007). Although much is known at the between-person level, far fewer studies have examined inthe-moment effects of ABP (for exceptions see Brondolo et al, 2003;Edmondson et al, 2015;Jacob et al, 1999;Kamarck et al, 2002;Ottaviani et al, 2011;Smith et al, 2012).…”

“…Although there are circumstances in which the betweenand within-person approaches converge, we cannot assume that results across levels will always concur (Kramer, 1983;Portnov et al, 2007). For example, it is widely recognized that exercise is good for cardiovascular health, but such conclusions tend to be drawn from between-person evidence.…”

Bladder Cancer in Iran: Geographical Distribution and Risk Factors

“…That is, the relations found in this study may not exactly be the same at individual level, and caution has to be taken when drawing conclusions. However, ecological fallacy should not be an issue if, as in our study, different levels of exposure are expected to be present in all areas (21). Hence, the results could be basically generalized to individual level.…”

“…And under certain conditions, their results are likely to emerge in individual levels (21). BlCa is one of major cancers in Iran, especially among men.…”