Aggregate, Disaggregate, and Hybrid Analyses of Ecological Risk Perceptions

Abstract

Laypeople's perceptions of health and safety risks have been widely studied, but only a few studies have addressed perceptions of ecological hazards. We assembled a list of 39 attributes of ecological hazards from the literatures on comparative risk assessment, ecological health, environmental conservation and management, environmental psychology, and risk perception. In Study 1, 125 laypeople evaluated 83 hazards on subsets of this attribute set. Factor analysis of attribute ratings (averaged over participants) revealed six oblique factors: ecological impacts, human impacts, human benefits, aesthetic impacts, scientific understanding, and controllability. These factors predicted mean judgments of overall riskiness, ecological riskiness, acceptability, and regulatory strictness. In Study 2, 30 laypeople each evaluated 34 hazards on 17 attributes and 3 dependent variables. Aggregate-level factor analysis of these data replicated the appropriate portion of the factor solution and yielded similar regression results. Parallel analyses at the individual-participant level yielded factors that explained less variance in judgments of overall riskiness, ecological riskiness, and acceptability. However, the decrease in explanatory power was much less than is often reported for disaggregate-level analyses of psychometric data. This discrepancy illustrates the importance of distinguishing between the level of analysis (aggregate versus disaggregate) and the focus of analysis (distinctions among hazards versus distinctions among participants). In a hybrid analysis, aggregate-level factor scores predicted individual participants' riskiness judgments reasonably well. Psychometric studies such as these provide a sound empirical basis for selecting attributes of ecological hazards for use in comparative risk assessment.

Environmental Health Risk Perception of a Nationwide Sample of Taiwan College Students Majoring in Engineering and Health Sciences

“…The above studies underscore that one's perception, in this case, risk perception is a result of complex and subjective psychological and mental processes; therefore, the study of risk perception truly requires collaboration across various disciplines. Willis et al (2005) systematically studied the methodological issues in psychometric studies and categorized the data analysis methods by the focus of analysis and the level of analysis. The hazard-focused approach, in which the data matrix of interest is hazard × attribute, focuses on understanding how a hazard is perceived differently from the others.…”

“…In some instances, studies have shown the classic psychometric factor space diagram of "dread" and "unknown" is mostly valid at the individual level and argued that the conventional aggregate-level approach can still provide useful information (Kraus and Slovic 1988;Marris et al 1997). As an alternative, Willis et al (2005) have proposed an approach that provides a fine balance between aggregate-and disaggregate-level analysis. The authors presented a hybrid analysis that uses the aggregate-level factor scores to predict individuals' riskiness judgments.…”

The Impact of Geography and Labor upon the Size of Job Agglomerations in Memphis, Tennessee

“…Instead of aggregating data to the job concentration level, disaggregate approach was used where the U.S. Census blocks represented the unit of analysis. Aggregated data mask variation among individual places; further, use of such data was criticized because of the inflation of the explanatory power of an analysis [56]. Accordingly, for this analysis, we used only those 1620 U.S. Census blocks which were part of the 64 identified employment concentrations (employment cluster, subcenter, or center).…”

Merging spatially variant physical process models under an optimized systems dynamics framework.

“…The determination to use this combination of methodologies is based on a series of studies that show: 1) surveys and questionnaires can quantify people's attitudes towards water allocation (Syme and Nancarrow, 1996); 2) informal elicitation techniques have similar results when compared with hardcopy surveys and improved participation (Willis et. al, 2005); and 3) non-market valuation may be more effective when completed as an open-ended elicitation (Satterfield, 2001;Satterfield et al, 2000 ) .…”