Development and Testing of an Abbreviated Numeracy Scale: A Rasch Analysis Approach
Article first published online: 15 MAR 2012
Copyright © 2012 John Wiley & Sons, Ltd.
Journal of Behavioral Decision Making
Volume 26, Issue 2, pages 198–212, April 2013
How to Cite
Weller, J. A., Dieckmann, N. F., Tusler, M., Mertz, C. K., Burns, W. J. and Peters, E. (2013), Development and Testing of an Abbreviated Numeracy Scale: A Rasch Analysis Approach. J. Behav. Decis. Making, 26: 198–212. doi: 10.1002/bdm.1751
- Issue published online: 12 MAR 2013
- Article first published online: 15 MAR 2012
- National Science Foundation. Grant Numbers: SES-0820197, SES-0517770, SES-0901036, SES-0925008, SES-082058
- National Institute on Aging. Grant Numbers: R01AG20717, P30AG024962
- decision making;
- individual differences;
- Rasch analysis;
- cognitive reflection test
Research has demonstrated that individual differences in numeracy may have important consequences for decision making. In the present paper, we develop a shorter, psychometrically improved measure of numeracy—the ability to understand, manipulate, and use numerical information, including probabilities. Across two large independent samples that varied widely in age and educational level, participants completed 18 items from existing numeracy measures. In Study 1, we conducted a Rasch analysis on the item pool and created an eight-item numeracy scale that assesses a broader range of difficulty than previous scales. In Study 2, we replicated this eight-item scale in a separate Rasch analysis using data from an independent sample. We also found that the new Rasch-based numeracy scale, compared with previous measures, could predict decision-making preferences obtained in past studies, supporting its predictive validity. In Study, 3, we further established the predictive validity of the Rasch-based numeracy scale. Specifically, we examined the associations between numeracy and risk judgments, compared with previous scales. Overall, we found that the Rasch-based scale was a better linear predictor of risk judgments than prior measures. Moreover, this study is the first to present the psychometric properties of several popular numeracy measures across a diverse sample of ages and educational level. We discuss the usefulness and the advantages of the new scale, which we feel can be used in a wide range of subject populations, allowing for a more clear understanding of how numeracy is associated with decision processes. Copyright © 2012 John Wiley & Sons, Ltd.