Experimental Designs
Experimental designs in psychology refer to the structured plans for conducting research to investigate cause-and-effect relationships. They involve manipulating independent variables to observe their effects on dependent variables. Common types of experimental designs include pre-test/post-test control group design, factorial design, and within-subjects design. These designs are essential for drawing valid conclusions about the impact of variables on behavior and mental processes.
7 Key excerpts on "Experimental Designs"
eBook - ePub- S Alexander Haslam, Craig McGarty(Authors)
- 2018(Publication Date)
- SAGE Publications Ltd(Publisher)
...Experimental design and causality in social psychological research. In C. Sansone, C. C. Morf, & A. T. Panter (Eds.), The SAGE handbook of methods in social psychology (pp. 237–264). Thousand Oaks, CA: SAGE. Experimental design: A checklist for research evaluation and improvement Table 4.1 Test Yourself 4.6** A researcher conducts an experiment to investigate the effects of positive mood on memory. Mood is manipulated by giving participants a gift. In the experiment, before they are given a memory test, half of the participants are randomly assigned to a condition in which they are given a box of chocolates, and the other half are given nothing. Which of the following statements is not true? Mood is a between-subjects variable. The experiment has two conditions. The experiment includes a control condition. The independent variable is manipulated within subjects. Experimental control eliminates potential threats to the internal validity of the experiment. Test Yourself 4.7* Which of the following is a researcher’s overall objective in using matching? To control for extraneous variables in quasi-Experimental Designs. To increase participants’ enjoyment of correlational research. To ensure that participants are randomly assigned to conditions. To ensure that groups of participants do not differ in age and sex. To ensure that groups of participants do not differ in intelligence. Test Yourself 4.8** Which of the following threats to validity is the most difficult to control by improving experimental design? Maturation effects. Cheating by experimenters. History effects. Sensitivity to demand characteristics. Experimenter bias. Test Yourself 4.9** Some researchers decided to conduct an experiment to investigate the effects of a new psychological therapy on people’s self-esteem. To do this they asked all their clients who were currently receiving treatment for low self-esteem to continue using an old therapy, but treated all their new clients with the new therapy...
eBook - ePubStudying Cities and City Life
An Introduction to Methods of Research
- Mark Abrahamson(Author)
- 2016(Publication Date)
- Routledge(Publisher)
...chapter 3 Experimental design Outline • Experiments introduced ∘ Manipulating the independent variable • Contrasting experiments and ethnographic studies • Experimentation in social science ∘ Urban experiments ∘ Helping behavior ∘ Climate change • Causal inference ∘ Temporal ordering ∘ Association ∘ Spuriousness ∘ Statistical and experimental control ∘ Theoretical congruence ∘ Types of causal reasoning • Experimental Designs ∘ One group design ∘ The classic experiment ■ Pre-test contamination ∘ More complex designs ∘ Simulating an experimental design • Assigning subjects to experimental conditions ∘ In a natural setting ∘ In a laboratory setting ∘ Contamination and blinding ∘ In Internet-based experiments • Internal and external. validity ∘ Internal validity ∘ External validity • Notes • Glossary The first thing that comes to many people’s minds when they think of an experiment is a laboratory. They imagine a white-coated scientist surrounded by test tubes. There is relatively little about social life in cities that can be examined in a laboratory, so if that was all there was to experimentation we would not be interested. However, the principles of experimental design can be applied outside of laboratories and utilized very effectively with other research methods. What is valuable about the principles of experimental design is their unmatched ability to enable an investigator to reach a conclusion concerning a causal connection between variables. To illustrate, consider the other everyday meaning in which to experiment typically means to change something, and then note its consequences. For example, a student may try re-writing notes after each lecture, rather than waiting until just before an exam, and see whether test scores improve. If the student was really anxious about grades, then the student might also attend class more often, spend more time reading assignments, participate more in classroom discussion, etc...
eBook - ePub- Alan Bryman(Author)
- 2003(Publication Date)
- Routledge(Publisher)
...In this chapter, the factors that facilitate the detection of causality from Experimental Designs will be elucidated. Second, because of the facility with which researchers employing Experimental Designs are able to establish cause and effect, the experiment is frequently perceived as a model research design. This point will be especially apparent when survey research, from which causal findings are less easy to establish, is examined. In everyday speech, we frequently employ the term ‘experiment’ very loosely to denote trying something out and observing the consequences of our action. Social scientists and others who write about experiments see them as involving something more than merely trying something out; in particular, the idea of ‘control’ is essential. The idea of control implies the elimination of alternative explanations of the apparent connection between a putative cause and a particular effect. We may say that we are going to ‘experiment’ with a different route when we drive to work one day; if we find that the time taken is a few minutes more, we should be very careful about saying that the alternative route was the cause of the greater time taken; the volume of traffic may not have been typical, and we may have driven more tentatively because of our unfamiliarity with the route. In other words, we have not controlled, and hence eliminated, these alternative possibilities. This notion is akin to the need to control the potentially contaminating effects of heat, light and humidity in the natural scientist’s laboratory. What we want to be able to demonstrate is that our supposed independent variable, and that variable alone, is the cause of variation in the dependent variable. On the other hand, to anticipate slightly some of the issues that will be examined below, conducting research on themes deriving from organization studies runs into some specific problems when the natural scientist’s laboratory is used as a yardstick...
- Bruce B. Frey(Author)
- 2018(Publication Date)
- SAGE Publications, Inc(Publisher)
...With the combined virtues of random assignment and counterfactual evidence provided a control group, experimental research designs are the gold standard for isolating causal mechanisms. However, Experimental Designs can be difficult to implement in the real-world environments such as classrooms and schools. For example, it is often difficult to assign (randomly, or otherwise) teachers in the same school to different conditions, to assign students to classrooms, and to assign students in the same classroom to different conditions. As a consequence, Experimental Designs in education often use schools (i.e., clusters) as the assignment unit whereby schools, along with every teacher and student in that school, are assigned to either the treatment or control condition. This approach typically requires many schools and so can be quite expensive to implement. Laura O’Dwyer See also Longitudinal Data Analysis ; Random Assignment ; Random Selection ; Threats to Research Validity ; Validity ; Validity Generalization Further Readings Campbell, D. T., & Stanley, J. C. (1963). Experimental and quasi-Experimental Designs for research. Chicago, IL : Rand McNally. Campbell, D. T., & Stanley, J. C. (1966). Experimental and quasi-Experimental Designs for research. Chicago, IL : Rand McNally. Cook, T. D., & Campbell, D. T. (1976). The design and conduct of quasi-experiments and true experiments in field settings. In M. Dunnette (Ed.), Handbook of industrial and organizational psychology (pp. 228 – 293). Chicago, IL : Rand McNally. Cook, T. D., & Campbell, D. T. (1979). Quasi-experimentation: Design … analysis issues for field settings. Boston, MA : Houghton Mifflin. Cook, T. D., & Shadish, W. R. (1994). Social experiments: Some developments over the past 15 years. Annual Review of Psychology, 45, 545 – 580. Fraenkel, J. R., & Wallen, N. E. (2011). How to design and evaluate research in education (6th ed.). Boston, MA : McGraw-Hill. Gall, M. D., Borg, W. R., & Gall, J...
eBook - ePub- James P. Neelankavil(Author)
- 2015(Publication Date)
- Routledge(Publisher)
...8 Experimental Research Experimentation is a type of conclusive research in which the objective is to understand cause-and-effect relationships between variables. L EARNING O BJECTIVES After reading this chapter, students should be able to • Understand causal research • Know what the conditions for causality are • Understand validity in Experimental Designs • Know the various Experimental Designs • Understand the application of designs for various research objectives • Be familiar with the use of Experimental Designs in test marketing • Understand the general benefits of using Experimental Designs • Know the problems associated with Experimental Designs International executives need to understand why certain decisions they make have a greater impact on business results than some others. Will sales always rise when prices are lowered? Will factory workers always increase output when offered incentive bonuses? Causal research can help with these types of decisions. By scientifically isolating variables that have a greater impact on an outcome, managers can improve their decision-making skills. Experiments are widely used in product testing, tradeoff analysis, and test marketing. 1 Most causal research techniques are able to isolate those variables that have an effect on another variable. Furthermore, they help in determining the nature of the relationship between the cause variable and the effect variable, and they help predict the effect. Most causal research designs are structured and require careful planning. The major causal research technique used in business settings is experimentation. With the advent of computers and the ability to customize them easily, many researchers are using this technology...
- Steven G. Rogelberg(Author)
- 2016(Publication Date)
- SAGE Publications, Inc(Publisher)
...Experimental Designs Experimental Designs Eugene F. Stone-Romero Eugene F. Stone-Romero Stone-Romero, Eugene F. 473 476 Experimental Designs Eugene F. Stone-Romero The validity of inferences stemming from empirical research in industrial and organizational psychology and allied disciplines is a function of a number of factors, including research design. Research design has to do with the plan, structure, or blueprint for a study. The literature indicates that among the components of such a plan are (a) the experimental design type (i.e., randomized experiment, quasi-experiment, and nonexperiment); (b) the study setting (e.g., created for the purpose of doing research); (c) the numbers and types of study participants; (d) the way in which the variables considered by the study are operationally defined; and (e) the techniques that will be used to analyze the data produced by the study. The focus here is on the randomized experiment. It differs in important ways from both nonexperimental and quasi-experimental design types. Prior to considering the nature of randomized experiments, this entry addresses several issues concerning the validity of inferences stemming from empirical research. The same issues apply to quasi-experiments and nonexperiments, as well. Factors Affecting the Validity of Research-Based Inferences The overall correctness of inferences (e.g., research-based conclusions, recommendations for practice) stemming from a study is a function of its design and the manner in which it is conducted...
eBook - ePub- E. Bright Wilson(Author)
- 2012(Publication Date)
- Dover Publications(Publisher)
...7. The wise choice of experimental material may greatly reduce experimental difficulties. For example, in biological work the species selected may make the difference between success and failure. It has been pointed out that the choice of the fruit fly Drosophila by T. H. Morgan for his classical studies in genetics was crucial because new generations were produced every 2 weeks. Similarly, the successful demonstration of the virus nature of yellow fever rested on the discovery that a certain species of monkey was susceptible to the disease and so could be used as an experimental subject. It should be emphasized, however, that mere experimental convenience should not be allowed to outweigh more basic considerations. The easy experiment may not answer the right questions. 4.5. Controls and Standards The ideal experiment is sometimes described as one in which all relevant variables are held constant except the one under study, the effects of which are then observed. This pattern is not necessarily even theoretically the best in many cases, as will be seen, and in almost all actual situations cannot be practically achieved. Consequently some device is needed to help correct for the effect of other variables which may be changing in an unknown or uncontrollable way during the experiment. One such device is the introduction of controls. These are similar test specimens which are subjected to as nearly as possible the same treatment as the objects of the experiment, except for the change in the variable under study. Controls are particularly necessary in medical research and many useless treatments have obtained a foothold because of alleged “experiments” which in fact gave misleading results because no controls were employed. Two contrasting examples are the “gold” treatment for tuberculosis and the use of streptomycin for the same disease...
