Through which of the following methods of research 'cause and effect relationship' is focused?

Research is a systematic investigation to search for new facts in any branch of knowledge. It helps to arrive at new conclusions.

William C. Emory in the book 'Business Research Methods' defines, "research is any organised inquiry designed and carried out to provide information for solving a problem."

Methods of research:

Experimental method:

• Experimental research is a study that adheres to a specific research design.
• It includes a hypothesis, a variable that can be manipulated by the researcher, and variables that can be measured, calculated, and compared.
• It is undertaken when a researcher wishes to trace the cause and effect relationship between defined variables.
• Experimental research is undertaken mostly in a controlled environment.  

Therefore, in the Experimental method research 'cause and effect relationship' is focused.

Historical method:

• Historical research involves studying, understanding, and interpreting past events.
• The purpose of historical research is to reach insights or conclusions about past persons or occurrences.
• It entails more than simply compiling and presenting factual information; it also requires interpretation of the information.

Ex post facto research:

• Ex post facto research design is a method in which groups with qualities that already exist are compared on some dependent variable.
• It is a category of research design in which the investigation starts after the fact has occurred without interference from the researcher.

Case study method:

• A case study is a research approach that is used to generate an in-depth, multi-faceted understanding of a complex issue in its real-life context.
• It is an established research design that is used extensively in a wide variety of disciplines, particularly in social sciences.
• It aims to analyze specific issues within the boundaries of a specific environment, situation, or organization.