Fieldwork for the first wave lasted 54 days (7 weeks and 5 days), with the online survey launching on 3rd June 2020. Telephone fieldwork started on the 29th June and lasted for 4 weeks, with a smaller number of study participants being assigned to the telephone interviewers two weeks earlier than the others.
The first wave of the ELSA COVID-19 Substudy closed on the 26th July 2020, achieving a final response rate of 75% (7,040 completed interviews from a sample of 9,392 study participants), with 83% of the surveys completed online and 17% on the phone.
The web fieldwork for the second wave started on 4th November 2020 and lasted 47 days (6 weeks and 5 days, one week shorter than the first wave). The telephone fieldwork started one week after, on 11th November.
The second wave of the ELSA COVID-19 Substudy closed on 20th December 2020, confirming the same response rate and split in modes witnessed in the first wave with a final response rate of 75% (6,794 completed interviews, with fewer study participants issued to the second wave due to refusals and ineligibility) A total of 83% of the surveys were completed online and 17% on the phone.
More detail can be found in the methodological report.
If you have any queries about the data collection, please contact NatCen.