The influence of crowds on consumer health decisions

an online prospective study

Annie Y S Lau, Trevor M Y Kwok, Enrico Coiera

Research output: Chapter in Book/Report/Conference proceedingChapter


This paper presents an online prospective study investigating whether the strength of social feedback, i.e. the proportion of persons who concur or do not concur with one's own answer to a question, influences the way one answers health-related questions. Two hundred and twenty-seven undergraduate students were recruited to use an online search engine to answer six health-related questions. Subjects recorded their pre- and post-search answers to each question and their level of confidence in these answers. After answering each question post-search, subjects were presented with a summary of post-search answers provided by previous subjects and were asked to answer the question again. There was a statistically significant relationship between the absolute number of others with a different answer (the crowd's opinion volume) and the likelihood of an individual changing an answer (P <.0001). Subjects' likelihood of changing answer increased as the percentage of others with a different answer (the crowd's opinion density) increased (P = 0.047). Overall, 98.3% of subjects did not change their answer when it concurred with the majority (i.e. > 50%) of subjects. When subjects had a post-search answer that did not concur with the majority, they were 24% more likely to change answer than those with answers that concurred (P <.0001). This study provides empirical evidence that strength of social feedback influences the way healthcare consumers answer health-related questions.

Original languageEnglish
Title of host publicationMedinfo 2010
Subtitle of host publicationProceedings of the 13th World Congress on Medical Informatics
EditorsC. Safran, S. Reti, H.F. Marin
Place of PublicationAmsterdam
PublisherIOS Press
Number of pages5
EditionPART 1
ISBN (Electronic)9781607505884
ISBN (Print)9781607505877
Publication statusPublished - 2010
Externally publishedYes
Event13th World Congress on Medical and Health Informatics, Medinfo 2010 - Cape Town, South Africa
Duration: 12 Sep 201015 Sep 2010

Publication series

NameStudies in Health Technology and Informatics
PublisherIOS Press
ISSN (Print)0926-9630
ISSN (Electronic)1879-8365


Other13th World Congress on Medical and Health Informatics, Medinfo 2010
CountrySouth Africa
CityCape Town

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