ValidityResearch is globally valid when a number of key concepts are used in the research design. The document must be organized and planned according to the criteria used in the field. Some important concepts to know include: validity, variable, operationalization, sample, measurement, measurement error, causality, plausible rival explanations, hypothesis, reliability, and unit of analysis. The researcher must learn to apply each key concept in an effort to make the study useful. These concepts will be reviewed individually so that you can understand how to apply them when writing a research paper. It is important to have validity in research. Validity is the best approximation of the truth of a given proposition, inference, or conclusion. It refers to the many conclusions drawn about the quality of different parts of the research methodology. It provides concrete data on the cause and effect construct. There are four main types of validity: conclusion, internal, constructive and external. External validity determines whether you can generalize the study's causal relationship to other people, places, or times. The researcher can argue that the research findings have implications for other groups and individuals in other contexts and at other times. Construct validity is reviewed if you have properly operationalized the ideas of cause and effect when there is a causal relationship in the study. Internal validity is used to determine whether the relationship is causal when you can say that the study program or treatment caused the study results. Conclusion validity is used to determine whether there is a relationship between cause and effect. All four types of validity are important in the middle of a paper...in research, they are valuable and necessary. Researchers must spend time and effort understanding key research concepts to be reliable and valid. From the beginning to the end of research, the researcher must organize the article consistently with the methods. The task is not always easy to manage, but if the person writing the research understands the principles and key notes for writing research, then the results and the time spent to achieve the objective will be positive. Therefore, one must spend time learning and using the concepts according to the study being written. Works CitedMeltzoff, J. (2008). Critical thinking about research: psychology and related fields. Washington, DC: American Psychological Association. Trochim, W. and Donnelly, J. (2008). The Research Methods Knowledge Base, 3rd ed. Mason, OH: Cengage.