Methods
Making Contact
How Were Potential Participants Contacted for the First Occasion of Measurement (T1)?
1.908 people (see Samples) were sent a letter providing basic information about the aims of the study. A date was suggested on which a trained research assistant would visit the potential participant to talk about the study. If there was no negative reaction to this letter, the research assistant visited the potential participant on the announced day and tried to convince him or her to take part in BASE. Different levels of participation were possible, but the aim was to convince as many people as possible to take part in the 14-session Intensive Protocol.
516 people were finally won as participants: 43 men and women in 6 age groups (70–74, 75–79, 80–84, 85–89, 90–94, 95+ years).
Cross-Sectional Assessment
Multidisciplinary Intake Assessment at T1, Repeated at all Following Occasions
The first session of the study was designed to gain as much basic information as possible at an early stage. On average, it took 90 minutes to answer the 100 questions on a wide range of topics. Measures important to each of the involved research units were assessed. This multidisciplinary instrument was repeated at every occasion of measurement.
The first 16 questions of the Intake Assessment corresponded to a Short Initial Assessment that already provided some important multidisciplinary information. This part of the interview could also be answered in a written questionnaire or on the telephone. The data collected at this level was particularly useful for the selectivity analyses (see Samples).
Intensive Protocol In 14 Sessions at T1
The Intensive Protocol was designed to assess the many facets of old age and aging using a variety of standardized instruments and measures selected by the four research units on the basis of their previous work. Except for three medical sessions (11, 13, and 14) that were carried out at the hospital, all assessments took place at the participant's home, be it a institution or a private household. Most sessions were performed by trained research assistants, but the geriatric, psychiatric, and dental examinations were carried out by trained physicians. On average, the sessions lasted 90 minutes.
Sequence of Data Collection
| Session | Content | |
| Multidisciplinary Intake Assessment (Session 1) | ||
| 1 | Short Initial Assessment/Baseline protocol/Observational protocol | |
| Intensive Protocol (Sessions 2-14) | ||
| 2 | Sociology I (Family of origin and employment history) | |
| 3 | Sociology II (Family history and family relationships) | |
| 4 | Sociology III (Economic situation and activities) | |
| 5 | Psychology I (Intelligence and intellectual functioning) | |
| 6 | Psychology II (Social relationships) | |
| 7 | Psychiatry I (Neuropsychological tests) | |
| 8 | Psychology III (Self and personality) | |
| 9 | Psychiatry II (Yesterday Interview and psychiatric scales) | |
| 10 | Internal Medicine and Geriatrics I (Medical interview) | |
| 11 | Internal Medicine and Geriatrics II (Physical examination) | |
| 12 | Psychiatry III (Psychiatric examination) | |
| 13 | Internal Medicine and Geriatrics III (Dental examination) | |
| 14 | Internal Medicine and Geriatrics IV (qCT, ultrasound imaging) |
Measures
Methods applied by the Sociology/Social Policy Unit included a life history instrument developed in earlier research, items from the German Socioeconomic Panel (GSOEP) questionnaire, Wegener's Magnitude Prestige Scale, etc.
Measures used by the Psychology Unit ranged from a computerized battery of standard intelligence tests, standard measures of personality and self-related beliefs, open-ended self-descriptions, and a questionnaire about coping styles, to a structured interview about social life and support networks.
The Psychiatry Unit applied standard psychiatric measures such as the Brief Psychiatric Rating Scale, the "Geriatric Mental State, Version A" (GMSA) interview, the Center for Epidemiologic Studies-Depression Scale (CES-D), and questionnaires dealing with, for example, medication use, the utilization of medical care, and subjective illness beliefs. In addition, consensus conferences were conducted together with the Internal Medicine/Geriatrics Unit to validate the diagnostic categories and to evaluate the medication.
In addition to a standardized medical anamnesis, a full-body, noninvasive medical and dental examination was conducted by the Internal Medicine/Geriatrics Unit. Furthermore, methods ranging from biochemical analysis to computer scanning were applied.
Longitudinal Assessments
Reduced Intensive Protocol in Six Sessions At T3 and T4
For the longitudinal reexamination, the original Intensive Protocol was cut back to six sessions: the Intake Assessment, a session organized by each of the research units, and a session including the Yesterday Interview. The instruments reemployed in these sessions represented a selection of those used in the first Intensive Protocol. For instance, changes of social participation over the years since the first interview were assessed, whereas retrospective accounts of participants' employment history were not documented again.
Assessment Protocol In Three Sessions at T5 and T6
Three sessions were conducted entailing a repeat of the Intake Assessment that was enriched by Psychiatry measures, a dental examination and repeats of measures of the Psychology Unit.
Assessment Protocol in Seven Sessions at T7
After a repeat of the Intake Assessment enriched by Psychiatry measures, a burst of six identical Psychology sessions was carried out within two weeks.
Assessment Protocol in Seven Sessions at T8
After a repeat of the Intake Assessment enriched by Psychiatry measures, two sessions covered repeats of psychological measures and two sessions repeated medical measures (including a detailed anamnesis and examination). Further two sessions involved a repeat of the dental examination.
Data Analysis
How Are Longitudinal Data Analyzed?
The adequate analysis of longitudinal data faces challenges because of the typical changes of samples over time. Methodological innovation has been pursued in BASE to deal with such challenges (e.g., Brandmaier et al., 2014; Ghisletta et al. 2014).
Selected Publications
Baltes, P. B., Mayer, K. U., Helmchen, H., & Steinhagen-Thiessen, E. (2001). The Berlin Aging Study (BASE): Sample, design, and overview of measures. In P. B. Baltes & K. U. Mayer (Eds.), The Berlin Aging Study: Aging from 70 to 100 (pp. 15–55). Cambridge University Press.
Brandmaier, A., von Oertzen, T., McArdle, J., & Lindenberger, U. (2014). Exploratory data mining with structural equation model trees. In J. J. McArdle & G. Ritschard (Eds.), Contemporary issues in exploratory data mining in the behavioral sciences (pp. 96–127). Routledge. Full text
Delius, J. A. M., Düzel, S., Gerstorf, D., & Lindenberger, U. (2015). Berlin Aging Studies (BASE and BASE-II). In N. A. Pachana (Ed.), Encyclopedia of geropsychology. Springer. https://doi.org/10.1007/978-981-287-080-3_44-1
Ghisletta, P. (2014). Recursive partitioning to study terminal decline in the Berlin Aging Study. In J. J. McArdle & G. Ritschard (Eds.), Contemporary issues in exploratory data mining in the behavioral sciences (pp. 405–428). Routledge.
Nuthmann, R., & Wahl, H.-W. (2007). Technical report for the first wave of the Berlin Aging Study: Field procedures and sample recruitment strategy (1990–1993) (Materialien aus der Bildungsforschung Nr. 82). Max Planck Institute for Human Development. Full text
See also Publications