Methodological note – Covid-19
During the SILC 2020 fieldwork, the Covid-19 pandemic broke out in Belgium. The measures taken to contain the pandemic had a substantial impact on data collection:
- Interview method: In SILC, interviews are usually conducted face to face (CAPI). During and after the lockdown, declared in March 2020, the interviews were conducted by telephone (CATI).
- Discriminatory effect of the method: The CATI method has been discriminatory at several levels:
- New households were difficult to reach because their phone number is not known.
- Inclusion of people hard of hearing and people without a phone, among others, was particularly difficult.
- Response rate: The difficult accessibility of the new households resulted in a significantly lower response rate for this group than usual in SILC.
- Fieldwork period: As a result of the lockdown declared in March 2020, fieldwork was temporarily halted. Interviews for which an appointment had already been made were conducted by telephone. In mid-April, the fieldwork was resumed for the panel households. After a test in June, fieldwork for the new households was also resumed in mid-July.
- Progress of the fieldwork: SILC is not constructed as a survey representative of the entire reference period. The fieldwork progressed significantly faster in Brussels (50% of the interviews by the end of April), than in Wallonia (28%) and Flanders (17%). In the summer months of July and August, 6% of the Brussels interviews were conducted, compared to 17% of the interviews in Flanders and 18% of the interviews in Wallonia. However, the daily reality of the months of March-April 2020 was very different from that of July-August 2020.
- Bias in the realised sample: Some households we found easier to reach at home, others we didn't, some households were practically harder to reach (e.g. those living in buildings), some households were in survival mode and couldn't take part, some households had more time, some households were reluctant towards the government because of the far-reaching restrictions imposed by the same government, ...
All these aspects have an impact on the results. However, these cannot be distinguished and examined from each other. This makes it difficult to compare the results of SILC 2020 with those of SILC 2019.