While doing surveys for research, you can either take a onetime approach, getting information at a particular point of time, or you can be wiser and adopt a method that measures the opinions and responses of people at different points in time. This second approach is also known as longitudinal surveys, probably named so because of the relation between time and longitudes. This methodology is used a lot by students who pursue social science research, medicine or ecology.
Taking this approach becomes necessary for making a comparison of responses, or tracking the changes in the preferences of people over time. Without this comparison, many studies would be meaningless. There can be three types of longitudinal surveys. The first is trend study, wherein you would select a sample from the entire population, which changes every year or every quarter. An example for this can be considering the data for a class, which will have new students every year. The image below shows a comparison of various skills of students for four years.
Another type of longitudinal survey can be Cohort study. A cohort is a group which has the same characteristics. So, in such a study, all the members of a group are studied over time. The observation can be for a group based on culture, ethnicity, education level, caste, economic background or age.
The last category is that of panel studies. This will be useful to you when you wish to follow the progress of a particular group of people over time. Here the subjects will be the same, but the data will change every time you collect a sample. For evaluating the contribution of a course to the development of skills and aptitude of students, the same set of students will form the sample group over the duration of the course. This period might be a few months, or some years. So, if you intend to use cohort study, plan well in advance to be able to finish the research in time. Also, keep a track of the members of the group that you choose. If you end up providing data for just half the population in the last cycle, the study is only 50 per cent complete. For Help in Dissertation Data analysis and Research Methodology, contact us at info@dissertationindia.com or call at .
