The survey within the framework of PREFER I was a follow-up to the German Ageing Survey (DEAS). All participants from PREFER I had previously participated in the third wave of the German Ageing Survey. The following selection criteria were applied:


  • DEAS-participation: Base Sample 2008
  • Age: 65 years or older
  • State of health: at least two diseases from a list of diseases (DEAS)
  • Consent to further participation: written consent to address storage for purposes of contact for further interviews

The realized sample of the first PREFER survey comprises 309 (of 443) persons.

A computer-assisted personal interview (CAPI, n = 309), various short-term physical and cognitive performance tests (lung function test, sit-to-stand test, digit-symbol-test) and a full survey of all medication were conducted at the first point of measurement in March 2009 (t1). In addition, participants were asked to complete a questionnaire (n = 303). In June 2009 (t2), a first repeat survey was conducted and a questionnaire was used again (n = 252). In September 2009 (t3), a final third survey was conducted, using a CAPI (n = 277), short tests (pulmonary function test, memory test, word fluidity test) and a questionnaire (n = 276). Several questions of the oral interviews and the supplementary written questionnaire (drop-off) are taken from the survey program of the German Ageing Survey (DEAS).

Documentation of the PREFER instruments and the codebook can be found here (available in German only).

As all PREFER participants are also DEAS respondents, data from the PREFER survey can be linked to data of DEAS waves from 2008 onwards, using the anonymous respondent ID (variable fallnum) as a unique identifier.