New study improves 'crowd wisdom' estimates

April 18, 2018

In 1907, a statistician named Francis Galton recorded the entries from a weight-judging competition as people guessed the weight of an ox. Galton analyzed hundreds of estimates and found that while individual guesses varied wildly, the median of the entries was surprisingly accurate and within one percent of the ox's real weight. When Galton published his results, he ushered the theory of collective intelligence, or the "wisdom of crowds," into the public conscience.

Collective wisdom has its limits, though. In a new study published in the Journal of the Royal Society Interface, researchers Albert Kao (Harvard University), Andrew Berdahl (Santa Fe Institute), and their colleagues examined just how accurate our collective intelligence is and how individual bias and information sharing skew aggregate estimates. Using their findings, they developed a mathematical correction that takes into account bias and social information to generate an improved crowd estimate. In the study, their corrected measures were more accurate than the mean, median, and other traditional statistics.

"There is growing evidence that the wisdom of crowds can be really powerful," Kao says. "A lot of studies show that you can calculate the average of estimates and that average can be surprisingly good."

"However," adds Berdahl, "there is a great deal of evidence that people have strong biases in estimation and decision tasks."

The researchers recruited over 800 volunteers to participate in the study and asked each participant to guess the number of gumballs in a jar, which ranged over several orders of magnitude from 54 to more than 27,000. Additionally, they quantified how individuals incorporate social information into their own opinion. To do so, the researchers offered participants fake details about other people's guesses and allowed them to change their estimate in light of that information.

Kao's team found that while estimates varied considerably, they were highly predictable. People tended to guess numbers smaller than the actual value and guessed a wider range of numbers for larger jars. Social information also plays a role in collective wisdom. For example, the simulated social information revealed that peer advice more strongly influenced an individual if the knowledge suggested the actual number of items was higher than the guesser's initial estimate. Smaller guesses, even if more accurate, appear to be more frequently discounted.

The findings define a clear set of rules for collective estimation, which in turn provide insight into why we observe the wisdom of crowds. This understanding can improve group wisdom in a variety of settings. Whether guessing the weight of a fat ox or predicting the outcome of future elections, Kao and his colleagues have helped the crowd grow smarter.
-end-


Santa Fe Institute

Related Weight Articles from Brightsurf:

How much postmenopause weight gain can be blamed on weight-promoting medications?
Abdominal weight gain, which is common during the postmenopause period, is associated with an array of health problems, including diabetes and heart disease.

Commercial weight management groups could support women to manage their weight after giving birth
Women who were overweight at the start of their pregnancy would welcome support after they have given birth in the form of commercial weight management groups, University of Warwick-led research has found.

Rollercoaster weight changes can repeat with second pregnancy, especially among normal-weight women
Everyone knows that gaining excess weight during one pregnancy is bad, but clinicians rarely consider weight gains and losses from one pregnancy to the next -- especially in normal-weight women.

Early and ongoing experiences of weight stigma linked to self-directed weight shaming
In a new study published today in Obesity Science and Practice, researchers at Penn Medicine and the University of Connecticut Rudd Center for Food Policy and Obesity surveyed more than 18,000 adults enrolled in the commercial weight management program WW International, and found that participants who internalized weight bias the most tended to be younger, female, have a higher body mass index (BMI), and have an earlier onset of their weight struggle

Being teased about weight linked to more weight gain among children, NIH study suggests
Youth who said they were teased or ridiculed about their weight increased their body mass by 33 percent more each year, compared to a similar group who had not been teased, according to researchers at the National Institutes of Health.

Association between weight before pregnancy, weight gain during pregnancy and adverse outcomes for mother, infant
An analysis that combined the results of 25 studies including nearly 197,000 women suggests prepregnancy body mass index (BMI) of the mother was more strongly associated with risk of adverse maternal and infant outcomes than the amount of gestational weight gain.

Study: Faster weight loss no better than slow weight loss for health benefits
Losing weight slowly or quickly won't tip the scale in your favor when it comes to overall health, according to new research.

What your choice of clothing says about your weight
It's commonly said that you can tell a great deal about a person by the clothes they wear.

Stand up -- it could help you lose weight
You might want to read this on your feet. A new study published today in the European Journal of Preventive Cardiology found that standing instead of sitting for six hours a day could prevent weight gain and help people to actually lose weight.

Cash for weight loss
A new study, published in the journal Social Science and Medicine, has shown that selling rewards programmes to participants entering a weight loss programme is a low cost strategy to increase both the magnitude and duration of weight loss.

Read More: Weight News and Weight Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.