Quasi-Experimental Research vs. True Experiments

1635 WordsJan 1, 20137 Pages
Quasi-Experimental Research vs. True Experiments Unit 9 November 18, 2012 Introduction I will compare and contrast quasi-experimental research and true experiments by addressing their weaknesses and strengths. Throughout my project I will give a detailed description of my experimental method used, as well as a thorough justification of why I selected this method as well as my sampling plan. I will also identify the target population, any ethical issues and my expected results. I will discuss the internal validity, external validity, limitations to my conclusion as well as my recommendations for future research. True Experiments True…show more content…
Knowing how similar the groups were at the beginning of the study before any treatment began is another difficulty in quasi-experiments. Quasi-experiments lack important control mechanisms and have less internal validity. The factors that jeopardize external validity or generalizability are; pre-testing, differential selection, experimental procedures, and multiple treatment interference. Pretested individuals may be less or more sensitive to the appetite suppressant making them unrepresentative of the population who had not been pre-tested. The goal of external validity is to implement the findings observed in a controlled laboratory experiment with a specific controlled setting, with specific conditions that were tested, and with the specific individuals who participated outside in a natural environment and get the same results. The text states that the three question of external validity are: 1. Would the same findings occur in different settings (e.g., the “real world” rather than the lab or in different laboratories)? 2. Would the same findings occur with different conditions (e.g., different levels of treatment or different operational definitions of the independent and dependent variables)? 3. Would the same findings hold true for different participants (e.g., a different sample of participants from the same population or members of a different population)(Zechmeister, Zechmeister, & Shaughnessy, 2001, p. 163)?
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