Numeracy - Expanded (11-item) Scale

Lipkus, I. M., Samsa, G., & Rimer, B. K. (2001). General performance on a Numeracy Scale among highly educated samples. Medical Decision Making, 21(1), 37-44. doi: 10.1177/0272989X0102100105

See also the original 3-item Numeracy measure by Schwartz et al. (1997) and the further expanded 15-item Numeracy measure by Peters et al. (2007).

	Table of Contents
	Description
	History of Use
	References

Description:

Purpose		The Numeracy measures were designed to assess numeracy, which is the ability to understand and use numeric information. The 11-item measure adds 8 items to Schwartz et al.'s (1997) original measure. Specifically, the expanded 11-item measure assesses understanding of risk and fractions as well as chance, proportions, and percentages. See also the original Schwartz et al. (1997) 3-item measure and the expanded Peters et al. (2007) 15-item measure.
Questions		11 items using a mixed free-response and multiple-choice format
Sub-scales		N/A
Domain		Medical decision making Framing Affect in decision making
Psychometrics
Sample items		Which of the following numbers represents the biggest risk of getting a disease? 1 in 100 1 in 1000 1 in 10 If the chance of getting a disease is 20 out of 100, this would be the same as having a __% chance of getting the disease.

History of Use:

Scale Uses:
Numeracy x framing: High numerate (identified by median split) were less susceptible to attribute framing, F(1,96) = 5.6, p < .05, η2 = .11. (Study 1) Numeracy x framing: High numerate (median split) were less susceptible to formatting differences (percentage vs. frequency), F(1,42) = 4.0, p < .05, η2 = .42. (Study 2) Numeracy: High numerate (median split) had more precise affect about choices, t(44) = -2.6, p < .01, d= .78. (Study 3) Numeracy: High numerate (median split) rated superior no-loss bet lower than inferior loss bet, t(89) = 3.1, p <.01, whereas low numerate rated bets equally. [Conclusion: More numerate have clearer feelings about probability but sometimes pick worse gamble.] (Study 4)		Peters et al. (2006)

References:

Scale:

Lipkus, I. M., Samsa, G., & Rimer, B. K. (2001). General performance on a Numeracy Scale among highly educated samples. Medical Decision Making, 21(1), 37-44. doi: 10.1177/0272989X0102100105

Other Versions of Numeracy:

Peters, E., Dieckmann, N. F., Dixon, A., Slovic, P., Mertz, C. K., & Hibbard, J. H. (2007). Less is more in presenting quality information to consumers. Medical Care Research and Review, 64(2), 169-190. doi: 10.1177/10775587070640020301

Schwartz, L. M., Woloshin, S., Black, W. C., & Welch, H. G. (1997). The role of numeracy in understanding the benefit of screening mammography. Annals of Internal Medicine, 127(11), 966-972.

Selected Uses:

Chapman, G. B., & Liu, J. J. (2009). Numeracy, frequency, and Bayesian reasoning. Judgment and Decision Making, 4(1), 34-40.

Fagerlin, A., Zikmund-Fisher, B. J., Ubel, P. A., Jankovic, A., Derry, H. A., & Smith, D. M. (2007). Measuring numeracy without a math test: Development of the Subjective Numeracy Scale. Medical Decision Making, 27(5), 672-680. doi: 10.1177/0272989X07304449

Garcia-Retamero, R., & Galesic, M. (2009). Communicating treatment risk reduction to people with low numeracy skills: A cross-cultural comparison. American Journal of Public Health, 99(12), 2196-2202. doi: 10.2105/AJPH.2009.160234

Lejarraga, T. (2010). When experience is better than description: Time delays and complexity. Journal of Behavioral Decision Making, 23(1), 100-116.

Peters, E., & Levin, I. P. (2008). Dissecting the risky-choice framing effect: Numeracy as an individual-difference factor in weighting risky and riskless options. Judgment and Decision Making, 3(6), 435-448.

Peters, E., Slovic, P., Vastfjall, D., & Mertz, C. K. (2008). Intuitive numbers guide decisions. Judgment and Decision Making, 3(8), 619-635.

Peters, E., Västfjäll, D., Slovic, P., Mertz, C. K., Mazzocco, K., & Dickert, S. (2006). Numeracy and decision making. Psychological Science, 17(5), 407-413. doi: 10.1111/j.1467-9280.2006.01720.x

Reyna, V. F., & Brainerd, C. J. (2008). Numeracy, ratio bias, and denominator neglect in judgments of risk and probability. Learning and Individual Differences, 18(1), 89-107. doi: 10.1016/j.lindif.2007.03.011

Reyna, V. F., Nelson, W. L., Han, P. K., & Dieckmann, N. F. (2009). How numeracy influences risk comprehension and medical decision making. Psychological Bulletin, 135(6), 943-973. doi: 10.1037/a0017327

Zikmund-Fisher, B. J., Smith, D. M., Ubel, P. A., & Fagerlin, A. (2007). Validation of the Subjective Numeracy Scale (SNS): Effects of low numeracy on comprehension of risk communications and utility elicitations. Medical Decision Making, 27(5), 663-671. doi: 10.1177/0272989X07303824

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