SAMPLING DESIGN IN A RESEARCH: How should we design the use of samples in research?

In Survey Research and Analytical Research

A researcher should describe 

• What is the target group of the study, and what is its nature?  How many numbers of the population; definite population or indefinite?  
• What Sampling Techniques did the researcher use to get a sample, and how about the Sample Size(n), Is the sample the best representative of the population?

In R & D Research

R&D Research is the research that focuses on the development of new approaches/new Materials/Innovations for providing convenience to humanity's life. In sampling please conduct it like this.

• What is the target group of applying the innovation[the experiment Group]; the target group may exist every year; you select a specific group of a specific year to be a Sample
• Who are the Key Informants in the process of developing the innovation i.e.; experts in the field, practitioners of the program, small group of the target group to try the prototype model

In Evaluation Research or The Program Effectiveness Research

Researchers prefer judging the quality of any Program; The Program is the target of the study[Object to Evaluate]

Researchers should do like this:- 

• Specify the indicators that will be evaluated.
• Data may be collected via evidence that reflects the quality of the Program, or 
• Ask for the stakeholders who work closely with the program[Sometimes using Questionnaire]