Perceived familiarity or factual knowledge? Comparing operationalizations of scientific understanding.

This study compares two frequently used operationalizations of understanding: factual knowledge and perceived familiarity. The authors argue that these measurements--which have been used interchangeably in past research--are conceptually distinct and should be treated as such. Using hierarchical linear ordinary least squares regression, this study provides evidence that factual knowledge and perceived familiarity are only slightly correlated and are influenced differently by predicting variables, such as media use and cognitive processing variables. As a result, the use of these measures may result in different assessments of the levels of public understanding, which has important implications for future policy decisions. [ABSTRACT FROM AUTHOR]