Longitudinal studies are used to study changes in individual or group behavior over an extended period of time by repeatedly monitoring the same subjects. In longitudinal research, results are recorded for the same group of subjects, referred to as a cohort, throughout the course of the study. The longitudinal study is an important research method in developmental psychology.
One major strength of longitudinal designs is that researchers are able to follow the same subjects over the entire period of a study. A longitudinal study that began in the 1960s, the Perry Preschool Project, assessed the children in the study at ages 4, 7, 10, and 12 and then again over a range of time as adults, providing researchers with strong statistical power in analyzing these changes.
Time, however can be a disadvantage of the longitudinal study because of the need of researchers to be involved in a study over a number of years. There's always a risk of losing some of the research subjects for any number of reasons. This means conclusions can only be made on the subset of the cohort who continued in the study.
There can also be unexpected complications that can arise during the course of a longitudinal study that can require changes to the study. For example, a longitudinal study of communication that began in the 1980s would have to change its questions to include communicating via cell phones, email, and texting technologies.
Longitudinal studies remain an important research strategy, although they are not frequently undertaken because of the time and expense involved.
The Perry Preschool Project allowed researchers to study the children as they matured and to record their developmental patterns throughout childhood into adulthood. They concluded that, because of the random assignment strategy, the preschool experience remains the best explanation for the difference in the performance of the two groups of children over the years.
A cross-sectional study is a method of observational research. Data is collected at one given point in time across a sample population or a pre-defined subset. Data is able to be collected easily and much more quickly, than a longitudinal study.
Because cross-sectional designs only capture a snapshot in time, with no follow-up research, it's impossible to get information on how a situation develops over time. In addition, due to the many differences of the participants - age, education, culture, etc. - cross-sectional studies may not accurately capture the true nature of causes of a problem being studied.
A simple survey is one of the most common tools used to gather data in a cross-sectional study. It can be collected relatively quickly and cheaply depending on the questionnaire. In the study below, researchers looked the management approaches of three different groups of early childhood professionals - preschool teachers, public health nurses, and speech-language pathologists, all of whom work with children who stutter.
Purpose
Early childhood professionals must accurately identify, refer, and treat children who stutter (CWS) within the scope of their respective roles to ensure each child receives the best possible care. What is the best way to achieve this goal?
Method - Survey
Conclusions of the Survey
A case study is an in-depth analysis of a unit — such as a person, group, organization, institution, community, or culture— usually over an extended time period. Research methods may involve extensive interviews with major participants or direct observations of how an organization operates, as well as how its members interact. The case study does not rely on laboratory experiments or survey data. Its focus is on events as they occur naturally and on existing relationships.
Case studies are used extensively across a range of social sciences such as sociology, political science, psychology, history, economics, planning, administration, public policy, education and management studies. A case refers to an individual, several individuals (as in multiple-case study), an organization or institution, or a culture. Researchers tend to use multiple sources of evidence, including archival records, interviews, direct observation, participant-observation, and/or physical artifacts. Most case study findings are written, but some appear as films, videos or audiotapes.
It's important to decide beforehand what criteria exists for judging the success of a case. Each person is unique and may react or interact differently than other members of the group. Criticism of case studies comes from those who claim that case studies lack objectivity, that findings cannot be generalized, or that sample sizes are too small. However it's been proven, with surveys, for example, that it is possible to draw reasonable conclusions from generalized findings.
All research methods depend upon the skill of the researcher, the context of the research, and the subject of analysis. In spite of various criticisms, case studies continue to provide some of the most interesting and inspiring research in the social sciences.
NOTE: Swiss psychologist Jean Piaget (1896-1980) was a leader in the case study method. In 1921, he published his findings from his systematic observations of how children learn. During his life, Piaget continued to develop his theory that a child’s mind evolves as it passes through a series of set stages to adulthood.
A Case Study of Early Educator Professional Development and Organizational Change
This case study investigated how a specific model, called the Breakthrough Series Collaborative designed as a model of professional learning helped five urban ECE programs adopt new trauma-informed practices in classrooms and the organization as a whole.
The case study explored the changes that occurred at the individual, classroom, and organizational levels
Results of the case study suggested changes occurred
