The 2015a Hellenic (Greek) National Election Voter Study has been conducted by the Research Team of Web-based surveys - School of Political Science, Aristotle University of Thessaloniki as part of the research project Web-based election studies of ELNES.
The survey was conducted as a mixed-mode survey (combination of web (CAWI) and telephone interviews (CATI)) in the period between June 12, 2015 and September 8, 2015. The recruitment of the respondents was done with a random selection of telephone numbers, using a Random Digital Dialling (RDD) method. The selected respondents who were contacted on the phone, were asked to provide their email address if they wanted to participate in a web survey conducted by Research Team of Web-based surveys - Department of Political Science, Aristotle University of Thessaloniki. Every email address collected was uploaded to the epolls.gr web survey system and an e-mail with the invitation and the link to the survey was sent to the respondent. The Web was the main mode of the survey and the telephone interview was used as an auxiliary method for the respondents who do not have internet access or email account. In addition, invitations were sent to about 400 respondents of the 2012 voter study who had indicated that they would be willing to participate in future ELNES surveys. The final dataset consists of 962 respondents to the web survey and 46 to the telephone interview.
You can download the Hellenic (Greek) National Study 2015a from ICPSR.