Working with User Agent Strings in Stata: The parseuas Command

Abstract

With the rising popularity of web surveys and the increasing use of paradata by survey methodologists, assessing information stored in user agent strings becomes inevitable. These data contain meaningful information about the browser, operating system, and device that a survey respondent uses. This article provides an overview of user agent strings, their specific structure and history, how they can be obtained when conducting a web survey, as well as what kind of information can be extracted from the strings. Further, the user written command parseuas is introduced as an efficient means to gather detailed information from user agent strings. The application of parseuas is illustrated by an example that draws on a pooled data set consisting of 29 web surveys.