Time for Tele-TTO? Lessons Learned From Digital Interviewer-Assisted Time Trade-Off Data Collection.

The preferred mode of administration of time trade-off (TTO) in large-scale valuation studies is face-to-face (personal) interviews facilitated by a trained interviewer. Geographical, financial or situational constraints could complicate personal TTO interviews. When facing such constraints, the use of digital interviews, in which trained interviewers facilitate through videotelephony software (i.e. tele-TTO) may be considered. This paper aims to guide researchers in how to approach tele-TTO interviews and discusses their advantages and disadvantages. The main advantages of tele-TTO compared to personal TTO are decreased need for travel and increased flexibility of interview scheduling, which could reduce costs and may foster representative sampling. Possible disadvantages of tele-TTO are partial loss of visual cues, complications with building rapport and possible selection effects that result from differences in interview preparation. Furthermore, the paper reports on lessons learned from a project in which both personal TTO and tele-TTO interviews were conducted. The results of this project suggest that although they require a different recruitment and interview process, tele-TTO interviews are feasible and provide flexibility to the interviewer. Furthermore, tele-TTO interviews yield largely similar results. Future research should explore the role of possible selection effects and respondents' perspective on tele-TTO interviews.