What is the name of the design in which subjects are randomly assigned to the experimental or control group and measured before and after the intervention?
RESEARCH DESIGNSThomas BevinsSummer 1999 Show
Research Designs are platforms to use to explore new knowledge in order to better understand phenomena, clarify explanations and identify causative factors. Although there are no real rules for choosing a design; one must realize the consequences for choosing one design over the other. One should choose the design that best attempts to address the conceptual issues presented. Some questions that would help you decide which quantitative design is most appropriate for your study include:
The purpose of an experimental design is to provide a structure for evaluating the cause-and-effect relationship between a set of independent and dependent variables. Some of the elements of an experimental design:
True experimental design: including random selection (random sampling), pretest/posttest, random assignment, manipulation of the levels of the independent variable(s), including a control group. Posttest-only design: (after-only design): you must assume that randomization assures pre-experimental group equivalence. Solomon four-group design: combines the true experimental and the posttest only. Allows you to evaluate the effect of the pretest on the posttest scores, and any interaction betwen the test and experimental condition. Factorial designs: Allows the researcher to examine the effects of one or more intervention on different factors or levels of variables in the study. Used for statistical control. Tends to increase sample size because you want to have enough subjects in each "cell" of the design. Counterbalanced (crossover) designs: when more than one intervention (treatment) is used, and you want to know the effect of manipulating the order in which the treatments are given. DePoy gives three criteria that need to be met to determine that a true experimental design is appropriate:
QUASI EXPERIMENTAL DESIGNS It is not always possible to implement a design that meets the three criteria of a true experimental study (manipulation, control and randomization). Quasi-experimental designs differ from experimental designs because either there is no control group or randomization cannot occur. Types of quasi experimental designs: 1. Nonequivalent control group design:
Pretest-posttest design: no randomization, not much control. Like a one-shot case study with a pretest. Static group comparison: still no randomization, but maybe a little more control. You have a "control group", but those subjects are non-equivalent, and there is no pretest to see how equivalent they might have been. NONEXPERIMENTAL DESIGNS These designs are used in situations where manipulation of an independent variable, control or randomization are not involved. These designs are focused to describe and measure independent and dependent variables. They are sometimes called descriptive research designs. Nonexperimental research does not prove causality. The goal is to describe phenomena and explore and explain relationships between variables. Types of non experimental designs: 1. Descriptive/Exploratory Survey Studies-
DePoy, E. & Gitlin, L. (1998). Introduction to research: Understanding and applying multiple strategies. St. Louis: Mosby. and LoBiondo-Wood, G., & Haber, J. (1998). Nursing research: Methods, critical appraisal, and utilization (4th ed.). St. Louis: Mosby. What is the design of experimental research method?What are The Types of Experimental Research Design? The types of experimental research design are determined by the way the researcher assigns subjects to different conditions and groups. They are of 3 types, namely; pre-experimental, quasi-experimental, and true experimental research.
What is the type of experimental research where the participants are randomly selected?What is random assignment? In experimental research, random assignment is a way of placing participants from your sample into different groups using randomization. With this method, every member of the sample has a known or equal chance of being placed in a control group or an experimental group.
What do you call the subjects in an experimental research design that is given an intervention?In experimental research, some subjects are administered one or more experimental stimulus called a treatment (the treatment group ) while other subjects are not given such a stimulus (the control group ).
Which of the following is a study in which subjects are randomly assigned to a control or treatment group?The randomised control trial (RCT) is a trial in which subjects are randomly assigned to one of two groups: one (the experimental group) receiving the intervention that is being tested, and the other (the comparison group or control) receiving an alternative (conventional) treatment (fig 1).
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