Mario Callegaro is senior survey research scientist at Google UK, London, in the Ads, Payments and User eXperience team (APUX) \. He works any survey related projects within his organization. He also consults with numerous other internal teams regarding survey design, sampling, questionnaire design and online survey programming and implementation. Mario holds a M.S. and a Ph.D. in Survey Research and Methodology from the University of Nebraska, Lincoln. Prior to joining Google, Mario was working as survey research scientist for Gfk-Knowledge Networks. He is associate editor of Survey Research Methods and in the editorial board of the International Journal of Market Research. Current research areas: web survey design, smartphone surveys, telephone / cell phone surveys, and questionnaire design in which he has published numerous papers, book chapters and conference presentations. He published (May 2014) an edited Wiley book titled Online Panel Research: A Data Quality Perspective together with Reginald P. Baker, Jelke Bethlehem, Anja S. Göritz, Jon A. Krosnick and Paul J.. Lavrakas. Mario also completed a book titled: "Web survey methodology" with Katja Lozar-Manfreda and Vasja Vehovar from the University of Ljubljana, Slovenia, published by Sage in June 2015.