The document summarizes a study that compared data collected via web surveys versus telephone surveys (CATI) for candidates in Greek political parties. Some key findings were: - Age and year of birth showed significant differences between the two modes, but education and income did not. - For most issues and policies there were significant differences in responses between the two modes, but these differences were reduced after matching respondents. - Direction of responses (e.g. agree vs disagree) were similar between modes, but intensity of responses sometimes differed significantly. - Recency and acquiescence effects may have driven some CATI respondents to choose the last response option more frequently compared to web respondents.

1. Mixed-mode surveys: Do different modes produce different data? Evidence from the Greek Candidate Survey Ioannis Andreadis Aristotle University of Thessaloniki

9. Chances to win X 2 = 14 . 6 p =0. 006 X 2 =5.8 p =0.218

10. Left-Right Self-placement X 2 =24. 6 P <0. 00 1 X 2 =2.4 p =0.661

11. Satisfaction with Democracy X 2 =6.0 p =0. 0 14 X 2 =1.4 p =0.234

12. Satisfaction with Democracy in EU X 2 =4.4 p =0. 0 37 X 2 =0.2 p =0.885

13. Our democracy needs serious reform X 2 =12 p =0. 0 07 X 2 =4.3 p =0.233

14. Income and wealth should be redistributed to ordinary people X 2 =13.4 p =0. 0 01 X 2 =3.5 p =0.177

15. Women should be free to decide on matters of abortion (direction) X 2 =6.4 p =0. 0 40 X 2 =4.5 p =0.107

16. Women should be free to decide on matters of abortion ( intension ) X 2 =15.8 p <0. 0 01 X 2 =11.1 p =0.004

17. Providing a stable network of social security prime goal ( intension ) X 2 =17.0 p <0. 0 01 X 2 =11.9 p =0.003