It is generally accepted that there is little that can be done about the ageing process; it is an inevitable course that humans have to experience with the passage of time. For diverse reasons, there are many studies conducted to understand the ageing phenomenon, for instance, people often want to know how to live better and productive lives during the advanced years. In order to come up with an informed knowledge about age specific issues, scholars used methods to study this occurrence such as the cross-sectional, longitudinal, and sequential methods of study.
Cross-sectional Design
The cross-sectional method typically utilizes the data that represent the whole adult population and observe them at the same specified period. The main feature of this type of examination is the use of observation at a certain point in time and that researchers obtain a structured set of data that enables systematic comparisons to be made between individuals or groups (Bond et al, 2007 p. 90). The advantage of this type of study is its simplicity and the immediate ability of observers to note the prevailing age trends in a specific group. Accordingly, it is based on the premise over the validity of the theory that the observation of subjects from different age brackets at the same point in time is the same as studying a single age group over time (Bond et al, 2007 p. 90). The disadvantages, however, are on the weakness of the above assumption, for instance, it does not consider other varying factors such as social class, gender or ethnic minority status (Bond et al, 2007 p. 90).
Longitudinal Method
The longitudinal method is used to provide for some the weakness of the cross-sectional design by using a repeated observation of the same subject over their entire life span (Shock et al, 1984 p. 9). However, the impracticability of repeated measurement of a subject's lifetime calls for the researches to be limited to a certain time period. The main advantage of using a longitudinal design is that it allows for the possibility of better estimating the age changes in an individual over a certain time, thus it permits the observation of the rate of aging. In addition to that, the frequent evaluation gives a more accurate and objective evidence for the study. Furthermore, there is a continuous interaction with the subjects allowing for other forms of study without the need to study another group. The disadvantage of of this study is that some of the participants may not have the commitment to continually participate, in addition to the little assurance over their geographic stability (Shock et al, 1984 p. 14).
Sequential Method
The sequential design is a system of studies that is a combination of both the cross-sectional, longitudinal as well as time-lag design (Bond et al, 2007 p.92). When fully used, it starts with a study of two groups or more using the cross-sectional method, consequently, these groups are then re-examined with the intent to generate longitudinal data. During the longitudinal study, additional groups are enlisted and these combined populations became the subject of repeated study. The advantage of the sequential method is that the researchers can cross-examine the information to assess the differing effects of age, cohort and time periods (Bond et al, 2007 p. 94). The disadvantage is that the complexity and sophistication of the approach tend to be expensive, that is, most often the research entails a large expense for the implementation and maintenance of the research settings.
REFERENCES
Bond, J., Peace, S.M., Dittman-Kohil, F., Westerhof, G., (2007) 'Ageing in Society', SAGE pp. 89-94
Shock, N.W., Greuclich, R.C., Andres, R., Arenberg, D., Costa, P.T. Jr., Lakatta, E., Tobin, J.D., (1984) 'Normal Human Aging: The Baltimore Longitudinal Study of Aging',National Institute of Health, 84(2450), pp. 5-18.
