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BASIC EXPERIMENTAL DESIGNS
Basic experimental design is one of the true experimental designs. It is the most frequently used experimental design. CHARACTERISITICS OF TRUE EXPERIMENTS A true experiment a scientific investigation Characterized by the following properties
- Manipulation -The experimenter does something to atleast some of the subjects in the study.
- Control - The experimenter introduces one or more controls over the experimental situation including the use of a control group.
- Randomization - The experimenter as signs subjects to a control or experimental group on a random basis. 1. Manipulation: The experimenter manipulates the independent variable by administering a treatment to some subjects by administering a treatment to some subjects and with holding it from others (or by administering some other treatment, such as a placebo) E.g. The color of a pediatric nurse’s uniform affects the degree to which children display positive affective behaviors, such as smiling and laughing during hospitalization. The independent or presumed causative variable in this example is uniform color, which could be manipulated by assigning some nurses white uniforms (for instance) and other nurses brightly colored uniforms. Thus, in this study we might compare, 24 RAGHU RN,,RM,,MN,,MBA
hours after hospitalization, the affective behaviour (the dependent variable) of two groups of Children: (1) Those cared for by white - uniformed nurses, and (2) those cared for by nurses in colored uniforms.
2. Control: The term control group to a group of subjects whose performance on a dependent variable is used as a basis for evaluating the performance of the experimental group (the group that receives the treatment of interest to the researcher) on the same dependent variable. E.g. If we wanted to evaluate the effectiveness of some nursing intervention on hospital patients, it would be unlikely that we would devise an experiment in which the control group of patients received no nursing cave at all. We would have to evaluate our new intervention, not against a control group receiving conventional methods of care. 3. Randomization: Randomization involves the placement of subjects in groups on a random basis. Random essentially means that every subject has an equal chance of being assigned to any group. E.g. The case in which only 10 women, all of whom have given birth to at least four children, constitute the entire sample for the study. Five of the 10 women are aged 35 Years or older, and the remaining five are younger than 35 Years of age. One would anticipate that a random assignment of RAGHU RN,,RM,,MN,,MBA
E.g. The nurse researcher might be interested to assess the effectiveness of diabetic teaching film. A group of clients with diabetes are randomly assigned to the experimental and the control group. Both groups are then pre tested on their knowledge of diabetes. Members of the experimental group watch the diabetic teaching film. Members of the control groups asked to read printed material that is similar to the information covered in the teaching film. Both groups are then post tested on their knowledge of diabetes. Finally, the difference between the posttest scores of the two groups is compared. E.g. Researcher tested the convective airflow blankets are more effective than conductive water flow blankets in cooling critically ill patients with fever. This design involves assigning patients to the two different types of blankets (the independent variable) and measuring the dependent variable(body temperature) twice , before and after the intervention .This scheme permits us to examine whether one blanket type is more effective that the other in reducing fever that is , with this design researchers can examine the change. E.g. shin and colleagues (2006) conducted on experiment to compare the relative effectiveness of hand acupuncture and mexibustion (an ancient form of heat therapy) in decreasing pain and “coldness” in Korean women who had a hysterectomy. Pain levels and digital infrared thermo graphic imaging measurements were obtained from all subjects both before and after the intervention. RAGHU RN,,RM,,MN,,MBA
E.g. Beckham (2007) evaluated the effectiveness of motivational interviewing on hazardous drinking in a sample of rural people at risk for alcohol dependence. Data an alcohol use (as measured by both self report and a liver function test) were collected both before and after the intervention among experimental control group members RAGHU RN,,RM,,MN,,MBA
the data on the dependent variable are collected only once after random assignment is completed and the experimental treatment has been introduced. E.g. O’ Sullivan and Jacob son (1992) used this design in their study of the impact of a program for adolescent mothers because it was impossible to measure infant outcomes before the birth of the infant. They carefully examined the two groups to ensure that the groups were equivalent at base line, So that they could be assured that random assignment had yielded equivalent groups .Other interventions, such as post operative pain management, can not be measured before surgery and require an after only design. Advantage: After only control group design is easier to carry out. The researcher does not have to be concerned with the reactive effects of the pretest on the post test. Disadvantage: The after only control group design should be used when is not possible to administer a pretest.. RAGHU RN,,RM,,MN,,MBA
