Since Dr. ling is studying altruism, and he visits a local playground and records how often children help each other, we call is Observational research design.
Observational research is used to answer a research question based solely on observations made by the researcher. There is no interference or manipulation of research subjects, and there are no control or treatment groups. These studies are frequently qualitative in nature and can be used for exploratory as well as explanatory research. Although quantitative observational studies are possible, they are uncommon.
Observational research is commonly used in the fields of hard science, medicine, and social science. This is frequently due to ethical or practical concerns that preclude the researcher from carrying out a traditional experiment. However, the lack of control and treatment groups makes drawing conclusions difficult, and there is a risk of confounding variables interfering with your analysis.
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