Independent Group Design

6 Key excerpts on "Independent Group Design"

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  eBook - ePub

  Research Methods in Human-Computer Interaction

  • Jonathan Lazar, Jinjuan Heidi Feng, Harry Hochheiser(Authors)
  • 2017(Publication Date)
  • Morgan Kaufmann

    (Publisher)

  Chapter 3

  Experimental design

  Abstract

  When designing an experiment, researchers need to determine the dependent and independent variables and how to measure or control those variables. There are three commonly adopted designs in human-computer interaction (HCI) studies: the between-group design, the within-group design, and the split-plot design. The between-group design is cleaner, avoids the learning effect, and is less likely to be affected by fatigue and frustration. But this design is weaker due to the high noise level of individual differences and usually requires larger number of participants. The within-group design effectively isolates individual differences and, therefore, is a much stronger test than the between-group design. Another advantage is that fewer participants are required. However within-group designs are more vulnerable to learning effects and fatigue. The appropriate design method needs to be selected based on the nature of the application, the participant, and the tasks examined in the experiment. Researchers should control potential bias in HCI studies through accurate and appropriate measurement devices and scales; clearly defined and detailed experimental procedures; carefully recruited participants; well-trained and professional experimenters; and well-controlled environments.

  Keywords

  Experimental design; Dependent variable; Independent variable; Between-group design; Within-group design; Split-plot design; Bias

  Experiments help us answer questions and identify causal relationships. Well-designed experiments can reveal important scientific findings. By contrast, ill-designed experiments may generate results that are false or misleading. Experiments have been widely used in the human-computer interaction (HCI) field to develop and modify user models or task models, evaluate different design solutions, and answer various other critical questions, such as technology adoption.

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  eBook - ePub

  Experimental Research Methods in Language Learning

  • Aek Phakiti(Author)
  • 2014(Publication Date)
  • Bloomsbury Academic

    (Publisher)

  It is to be hoped that experimental researchers will adopt this type of design as an alternative to group experimental designs. Unfortunately, it is beyond the scope of this book to cover single-case designs because they involve various complex theoretical and methodological considerations (e.g. how to deal with threats to the research validity), designs (e.g. multiple-baseline designs, changing-criterion designs, multiple-treatment designs and quasi-single-case designs) and statistical approaches (e.g. a time-series analysis). See, for example, Gast (2010), Kazdin (2011), and Morgan and Morgan (2009), who treat this type of design comprehensively in clinical, behavioral, and applied settings.

  True experimental designs

  We first address three important aspects of true experimental designs: Manipulation of independent variables , randomization and comparison groups .

  Manipulation of independent variables

  As discussed in Chapter 2 , an experimental study assumes that an independent variable causes changes in a dependent variable. As we will see in the designs discussed below, researchers manipulate independent variables in order to test their hypotheses. There are three common methods researchers have used to manipulate an independent variable (Johnson & Christensen 2008). The first is known as the presence or absence technique , the second is the amount technique , and the third is the type technique . When the presence or absence technique is employed, the experimental group will receive a treatment, whereas the control group will not receive the treatment. In a real-life situation, a control group may be a class taught using a traditional or regular method. For example, Rahimi (2013) examined whether training student reviewers can help them assist their peers through providing high-quality feedback. There were two groups (i.e. a trained group and an untrained group).

  When the amount technique

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  Research Methods for Social Psychology

  • Dana S. Dunn(Author)
  • 2012(Publication Date)
  • Wiley

    (Publisher)

  Between-subjects research designs We begin our review of research designs with what is probably the most common and, therefore, familiar type: The between-subjects design. A between-subjects (also known as between-groups) design is one where the experiment’s participants are exposed to one, and only one, level of an independent variable. The practical aspect of this definition is that each condition within an experiment comprises a different group of people (the standard posttest- only control group design fits this mold). Most of the sample experiments we considered thus far have been simple, two-cell or two-condition between-subjects designs: Participants were assigned either to an experimental treatment group or to a control group, and we subsequently compared what happened in each condition. Put another way, different groups of participants 4 Close your eyes and place an index finger anywhere on Table 4.3. Follow more or less the same procedure described above for random selection. You can begin to search for 10 two-digit numbers between 01 and 20 (skip numbers greater than 20). The first 10 names selected form one group, the remaining names the other group. Practice exercise. List the students in your class and, using Table 4.3, randomly assign half of them to one group, the remainder to another group. Additional exercise. How can you use Table 4.3 to assign the members of a convenience sample to one of four conditions in an experiment? Try to be creative but avoid making the assignment process too cumbersome. Be sure that you can explain the logic behind your strategy and do not violate the need for randomness. Other approaches to performing randomization can be found in Snedecor and Cochran (1980). As ideas, chance and randomization actually have a very interesting place in the history of ideas. For further exploration of their relevant history, consult Hacking (1975) or Gigerenzer et al. (1989). 92 Basic Experimental Design

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  Experimental Design and Statistics for Psychology

  A First Course

  • Fabio Sani, John Todman(Authors)
  • 2008(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  Finally, note that the process of specifying clearly and explicitly the methods (i.e., the operations) used to measure the DV is generally conceptualized as the operational definition of the DV. At this point, we have already presented the core structure of an experiment and the main terms and definitions that are used. In order to form a general picture, you may look at Figure 2.2. Note that in our experiment we are proposing to use different participants in the different conditions of the experiment. That is, 20 individuals are assigned to the THE NATURE OF PSYCHOLOGY EXPERIMENTS (I): VARIABLES AND CONDITIONS 14 participants complete a general reasoning test based on 10 logical problems & the number of problems correctly solved by each participant is counted (a participant’s score may range from 0 to 10) independent variable dependent variable watch an excerpt about a funny event experimental condition watch an excerpt about ordinary events control condition Figure 2.2 Terms and definitions in experimentation experimental condition (watching funny excerpt) and 20 different individuals are assigned to the control condition (watching neutral excerpt). This type of experimental design is called independent groups design (or between-subjects design). Now, you must be aware that not all experiments require assigning different people to the different conditions. In some cases it is possible, and even desirable, to use the same individuals in the different conditions. This type of design is called repeated measures design (or within-subjects design). The reasons why we may need or want to use one specific type of design rather than the other should become clear in the next chapter. Additional information (2.3) – Stimulus and response variables It should be noted that, in our example, the IV consists of exposing particip-ants to a specific stimulus, that is, an excerpt from a film. As a consequence, this IV can be defined as a stimulus variable .

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  Research Design in Counseling

  • Puncky Heppner, Bruce Wampold, Jesse Owen, Thompson, Puncky Heppner, Bruce Wampold, Jesse Owen, Mindy N. Thompson(Authors)
  • 2020(Publication Date)
  • Cengage Learning EMEA

    (Publisher)

  WITHIN-SUBJECTS DESIGNS The remainder of this chapter examines within-subjects designs. The hallmark of the within-subjects design is that it attempts to minimize error variance due to indi-vidual variation by having each participant serve as his or her own control. Similar to the between-groups design, participants are randomly assigned to groups or treat-ments, and independent variables are manipulated. The unique feature of the within-subjects design is that all participants are exposed to all of the treatment conditions; random assignment involves assigning people to different sequences of treatment. In this section we first provide an overview of two within-subjects designs: cross-overs and counterbalanced crossover designs. We then discuss the strengths and limitations of these within-subjects designs. Crossover Designs Suppose a researcher wanted to compare the effects of two treatments (independent variables)—test interpretation of the Strong Interest Inventory (SII) and work geno-grams—on a dependent variable, vocational clients’ career maturity. The researcher could use the within-participants design, as shown in Figure 11.4. Ob 1 , Ob 2 , and Ob 3 represent different observations—in this case, administration of a career inven-tory (say, the Strengths Self-Efficacy Scale; Tsai, Chaichanasakul, Zhao, Flores, & Lopez, 2014). Tx 1 represents the test interpretation treatment, and Tx 2 represents the genogram treatment. Copyright 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

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  Research for Effective Social Work Practice

  • Judy L. Krysik(Author)
  • 2018(Publication Date)
  • Routledge

    (Publisher)

  Experimental conditions in social work are the interventions used to produce positive changes. There are many possible experimental conditions. Interventions such as cognitive behavioral therapy, a change in the eligibility criteria for the Free and Reduced Price Lunch Program, and the implementation in a middle school of a curriculum aimed at preventing bullying are examples of experimental conditions.

  Mastering the material in this chapter and the two following chapters on sampling and measurement is critical to planning, conducting, and critiquing research. Although mistakes in the analysis of data at the end of a research study can be corrected, errors in specifying the study’s research design, how many subjects to study, or the data to be collected are costly. Moreover, once they are made, they cannot be undone. Decisions related to the choice of group research design, sampling, and measurement will impact how the evidence generated by the research study will be accepted and, ultimately, whether the results will be used to affect practice.

  By the end of this chapter you should be able to:

  ■    Describe the difference between group research design and case-level research design.

  ■    Suggest an appropriate group research design based on what the research question requires.

  ■    Understand group research design notation as the building blocks of research design.

  ■    Describe the strengths and weaknesses of the different types of group research designs.

  ■    Explain what is meant by internal validity and how threats to internal validity vary with the choice of group research design.

  ■    Explain what is meant by external validity and how threats to external validity vary with the choice of group research design.

  A PURPOSE-DRIVEN APPROACH TO SELECTING A GROUP RESEARCH DESIGN

  Different group research designs are appropriate for generating different kinds of information or knowledge. Chapter 3

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