PREFER

The survey conducted as part of PREFER I was a follow-up to the third wave of the German Ageing Survey (DEAS). All participants in the PREFER study had previously taken part in the 2008 DEAS survey. The following selection criteria were applied:

• DEAS participation: 2008 base sample
• Age: 65 years or older
• Health status: at least two conditions from a predefined list of illnesses (DEAS)
• Willingness to participate: written consent for address storage for the purpose of future contact and follow-up surveys

The realised sample for the first PREFER survey consisted of 309 out of 443 contacted individuals.

At the first wave of data collection in March 2009 (t1), the following components were included:

• a computer-assisted personal interview (CAPI, n = 309),
• several short tests of physical and cognitive functioning (lung function test, sit-to-stand test, digit symbol test),
• a complete record of all regularly taken medications,
• and a supplementary self-administered questionnaire (n = 303).

A first follow-up survey was conducted in June 2009 (t2), using a written questionnaire (n = 252).

The final wave of data collection took place in September 2009 (t3), and included:

• a second personal CAPI interview (n = 277),
• cognitive and physical short tests (lung function, memory test, verbal fluency test),
• and another self-administered questionnaire (n = 276).

Several questions from the interviews and the additional drop-off questionnaire were adapted from the DEAS survey instruments.

The documentation of the instruments used in PREFER and the associated codebook can be found here.

Since all PREFER participants were also part of the DEAS study, the PREFER data can be linked to DEAS waves from 2008 onward via the anonymised respondent ID (variable: fallnum).