Longitudinal Research Design

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1. LONGITUDINAL SURVEY RESEARCH DESIGN Presented by Shanta Rayamajhi Basnet Roll.no. 76155010 Nepal Open University

2. Outlines: Introduction Types of Longitudinal Research Strength Drawbacks Conclusion :

3. Introduction: The term ‘longitudinal’ is used to describe a variety of studies that are conducted over a period of time. It   is a  research design that involves repeated observations of the same variables (e.g., people) over short or long periods of time The purpose of using the same individuals or samples in the longitudinal study is to observe any measurable change over time . Often, as we have seen, the word ‘developmental’ is employed in connection with longitudinal studies that deal specifically with aspects of human growth.  

4. Introduction: Longitudinal designs are used to study individuals over time. In longitudinal designs, the participants may be different or the same people Example: In longitudinal study, a researcher wishes to look at the changes in cholesterol level in women above the age of 30 but below 40 years who have jogged regularly over the last 10 years. In longitudinal study setup, it would be possible to account for cholesterol levels at the start of the jogging regime, therefore longitudinal studies are more likely to suggest a cause-and-effect relationship .

5. Types of Longitudinal Research 1. Trend Studies 2. Cohort Studies 3. Panel Studies

6. Trend Studies Trend studies are longitudinal survey designs that involve identifying a population and examining changes within that population over time. Trend study samples different groups of people at different times from the same population. This type of study reveals the current situation of a specific research subject in a specific field by focusing on research topics . A popular example of this design is the Gallup Poll( an assessment of public opinion by the questioning of a representative sample, typically as a basis for forecasting votes in an election) , which is used during elections to monitor trends in the population of voters from the primary to the final election.

7. Cohort Studies Rather than studying changing trends in a population, the researcher may be interested in identifying a subgroup in the population, called a cohort, that possesses a common defining characteristic. A cohort study is a longitudinal survey design in which a researcher identifies a subpopulation based on some specifi c characteristic and then studies that subpopulation over time.

8. Cont . … For example, a cohort group of 18-year-olds is studied in the year 2001. Five years later (in 2006), a group of 23-year-olds is studied. (They may or may not be the same individuals studied in 2001.) Five years after that (in 2011), a group of 28-year-olds is studied. While the individuals studied each time might be different, they must have been 18 years old in the year 2001 to qualify as representatives of the cohort group.

9. Panel Studies A panel study is a longitudinal survey design in which the researcher examines the same people over time. A  panel  study involves a sample of people from a bigger population and is conducted at specified intervals for a longer period. One of the most important features of the panel study is that data is repeatedly collected from the same sample at different points in time . Example: The high school seniors studied in 1998 will be the same people studied in 2000, 1 year after graduation, and again in 2002, 2 years after graduation.

10. Strength of Longitudinal Research Longitudinal study can identify and relate to events. You can reveal chronology between events like long-term and short-term changes in variables, making this ideal for medical studies. Similarly, because a longitudinal study is carried out over a long period, it helps identify and establish a particular sequence of events. Longitudinal study provides meaningful insights that might not be possible with other forms of research like cross-sectional and similar studies. Longitudinal study allows researchers to trace development over a timeline instead of drawing conclusions based on a “snapshot” of data.

11. Drawbacks of Longitudinal Research Longitudinal studies are not cost-effective. Because they can run long, the costs can add up. An extended period may lead to longitudinal survey respondents dropping out during the study.  Participants may start to act unnaturally because they know they are under observation, which spoils the research. Continuity over the years may be challenging to maintain. For example, if the lead researcher of the study retires, the person replacing them may or may not have the same rapport. 

12. Conclusion: Longitudinal study is useful in science and medicine as well as many other fields. There are many reasons why a researcher might want to conduct a longitudinal study. One of the important reasons is, longitudinal studies give unique insights that many other  types of research  fail. Continuing from the example which is mentioned above, a researcher wants to establish a relation between the variables, “jogging” and “cholesterol” in this case, one of the first things that a researcher would need to establish in this kind of study is, to tell the most about the relationship. A few questions to ask would be, whether to compare cholesterol levels among different populations of joggers, non-joggers at the same point in time? Or to measure cholesterol levels in a single population of daily joggers over an extended period of time?

13. references file:///C:/Users/dell/Downloads/Cohen%20Manion%20Morrison%20(2).pdf https://www.questionpro.com/blog/cross-sectional-study-vs-longitudinal-study / https:// www.slideshare.net/nadianaseem5/longitudinal-research https://www.bing.com/news/search?q=filetype%3aintext%22+quantitative+research%22&qpvt=filetype%3aintext%22+quantitative+research%22&FORM=EWRE