@inproceedings{f5ee204a59ec4b4d9cec144eab0a3e9c,
title = "Easy does it: More usable CAPTCHAs",
abstract = "Websites present users with puzzles called CAPTCHAs to curb abuse caused by computer algorithms masquerading as people. While CAPTCHAs are generally effective at stopping abuse, they might impair website usability if they are not properly designed. In this paper we describe how we designed two new CAPTCHA schemes for Google that focus on maximizing usability. We began by running an evaluation on Amazon Mechanical Turk with over 27,000 respondents to test the usability of different feature combinations. Then we studied user preferences using Google's consumer survey infrastructure. Finally, drawing on the insights gleaned during those studies, we tested our new captcha schemes first on Mechanical Turk and then on a fraction of production traffic. The resulting scheme is now an integral part of our production system and is served to millions of users. Our scheme achieved a 95.3% human accuracy, a 6.7% improvement.",
keywords = "CAPTCHA, Empirical Methods, Quantitative Usability Testing and Evaluation, Security, User Studies, World Wide Web",
author = "Elie Bursztein and Angelika Moscicki and Celine Fabry and Steven Bethard and Mitchell, {John C.} and Dan Jurafsky",
year = "2014",
doi = "10.1145/2556288.2557322",
language = "English (US)",
isbn = "9781450324731",
series = "Conference on Human Factors in Computing Systems - Proceedings",
publisher = "Association for Computing Machinery",
pages = "2637--2646",
booktitle = "CHI 2014",
note = "32nd Annual ACM Conference on Human Factors in Computing Systems, CHI 2014 ; Conference date: 26-04-2014 Through 01-05-2014",
}