from the annals of...

We review the growing literature on health numeracy, the ability to understand and use numerical information, and its relation to cognition, health behaviors, and medical outcomes. Despite the surfeit of health information from commercial and noncommercial sources, national and international surveys show that many people lack basic numerical skills that are essential to maintain their health and make informed medical decisions. Low numeracy distorts perceptions of risks and benefits of screening, reduces medication compliance, impedes access to treatments, impairs risk communication (limiting prevention efforts among the most vulnerable), and, based on the scant research conducted on outcomes, appears to adversely affect medical outcomes. Low numeracy is also associated with greater susceptibility to extraneous factors (i.e., factors that do not change the objective numerical information). That is, low numeracy increases susceptibility to effects of mood or how information is presented (e.g., as frequencies vs. percentages) and to biases in judgment and decision making (e.g., framing and ratio bias effects). Much of this research is not grounded in empirically supported theories of numeracy or mathematical cognition, which are crucial for designing evidence-based policies and interventions that are effective in reducing risk and improving medical decision making. To address this gap, we outline four theoretical approaches (psychophysical, computational, standard dual-process, and fuzzy trace theory), review their implications for numeracy, and point to avenues for future research.

How Numeracy Influences Risk Comprehension and Medical Decision Making
by:
Valerie F. Reyna | Cornell University
Wendy L. Nelson and Paul K. Han | National Cancer Institute, Bethesda, Maryland
Nathan F. Dieckmann | Decision Research, Eugene, Oregon; and University of Oregon
Psychological Bulletin | 2009, Vol. 135, No. 6, 943–973

in a nutshell:

Despite the surfeit of health information from commercial and noncommercial sources, national and international surveys show that many people lack basic numerical skills that are essential to maintain their health and make informed medical decisions.

cool cash

Carolyn sends this link for our collective amusement:

'Cool Cash' card confusion

A LOTTERY scratchcard has been withdrawn from sale by Camelot - because players couldn't understand it.

[snip]

To qualify for a prize, users had to scratch away a window to reveal a temperature lower than the figure displayed on each card. As the game had a winter theme, the temperature was usually below freezing.

But the concept of comparing negative numbers proved too difficult for some Camelot received dozens of complaints on the first day from players who could not understand how, for example, -5 is higher than -6.

Tina Farrell, from Levenshulme, called Camelot after failing to win with several cards.

The 23-year-old, who said she had left school without a maths GCSE, said: "On one of my cards it said I had to find temperatures lower than -8. The numbers I uncovered were -6 and -7 so I thought I had won, and so did the woman in the shop. But when she scanned the card the machine said I hadn't.

"I phoned Camelot and they fobbed me off with some story that -6 is higher - not lower - than -8 but I'm not having it.

"I think Camelot are giving people the wrong impression - the card doesn't say to look for a colder or warmer temperature, it says to look for a higher or lower number. Six is a lower number than 8. Imagine how many people have been misled."

Well, I'm not laughing.

I can't figure out how to do the absolute value inequality word problem on C's homework tonight. Also, I can't figure out why it should be an absolute value problem in the first place.

That makes me a sad panda.