Identifying Confirmatory Bias in the Field: Evidence from a Poll of Experts

Rodney J. Andrews, Trevon Logan and Michael J. Sinkey

No 18064, NBER Working Papers from National Bureau of Economic Research, Inc

Abstract: Laboratory experiments have established the existence of cognitive biases, but their explanatory power in real-world economic settings has been difficult to measure. We estimate the extent of a cognitive bias, confirmatory bias, among experts in a real-world environment. In the Associated Press Top 25 College Football Poll expert pollsters are tasked with assessing team quality, and their beliefs are treated week-to-week with game results that serve as signals about an individual team's quality. We exploit the variation provided by actual game results relative to market expectations to develop a novel regression-discontinuity approach to identify confirmatory bias in this real-world setting. We construct a unique personally-assembled dataset that matches more than twenty years of individual game characteristics to poll results and betting market information, and show that teams that slightly exceed and barely miss market expectations are exchangeable. The likelihood of winning the game, the average number of points scored by teams and their opponents, and even the average week of the season are no different between teams that slightly exceed and barely miss market expectations. Pollsters, however, significantly upgrade their beliefs about a team's quality when a team slightly exceeds market expectations. The effects are sizeable-- nearly half of the voters in the poll rank a team one slot higher when they slightly exceed market expectations; one-fifth of the standard deviation in poll points in a given week can be attributed to confirmatory bias. This type of updating suggests that even when informed agents make repeated decisions they may act in a manner which is consistent with confirmatory bias.

JEL-codes: D01 D03 N32 (search for similar items in EconPapers)
Date: 2012-05
New Economics Papers: this item is included in nep-exp and nep-neu
Note: DAE
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (4)

Published as Rodney J. Andrews & Trevon D. Logan & Michael J. Sinkey, 2018. "Identifying Confirmatory Bias in the Field," Journal of Sports Economics, vol 19(1), pages 50-81.

Downloads: (external link)
http://www.nber.org/papers/w18064.pdf (application/pdf)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nbr:nberwo:18064

Ordering information: This working paper can be ordered from
http://www.nber.org/papers/w18064

Access Statistics for this paper

More papers in NBER Working Papers from National Bureau of Economic Research, Inc National Bureau of Economic Research, 1050 Massachusetts Avenue Cambridge, MA 02138, U.S.A.. Contact information at EDIRC.
Bibliographic data for series maintained by ().