QUASI-EXPERIMENTS What is a Quasi-Experiment?

Slides:



Advertisements
Similar presentations
Andrea M. Landis, PhD, RN UW LEAH
Advertisements

PSYC512: Research Methods PSYC512: Research Methods Lecture 13 Brian P. Dyre University of Idaho.
Experimental Design I. Definition of Experimental Design
Randomized Experimental Design
Non-experimental Designs
Group Discussion Describe the fundamental flaw that prevents a nonequivalent group design from being a true experiment? (That is, why can’t these designs.
QUASI-EXPERIMENTS w Compare subjects in different conditions on a DV w Lacks one or more criteria for an experiment (cause, comparison, control) w Interpreted.
Quasi-Experimental Designs
Design Conditions & Variables Explicating Design Variables Kinds of “IVs” Identifying potential confounds Why control “on the average” is sufficient Characteristics.
Quasi & Non-Experimental Designs
SINGLE CASE, QUASI- EXPERIMENT AND DEVELOPMENT RESEARCH.
Chapter 9 Group-Level Research Designs. CHARACTERISTICS OF “IDEAL” EXPERIMENTS Controlling the Time Order of Variables Manipulating the Independent Variable.
PSYC 235: Research Methods ALT DESIGN. Quasi Experiments.
Non-Experimental designs: Developmental designs & Small-N designs
Group Comparison Research
Lecture 17 Psyc 300A. HW 8: Setting Up a Factorial ANOVA Serve Other Serve Other Serve Self Serve Self Alone With Another
Non-Experimental designs: Developmental designs & Small-N designs
Group-Level Research Designs
© 2005 The McGraw-Hill Companies, Inc., All Rights Reserved. Chapter 10 Using Specialized Research Designs.
Questions What is the best way to avoid order effects while doing within subjects design? We talked about people becoming more depressed during a treatment.
Non-Experimental designs
Group Discussion Describe the similarities and differences between experiments , non-experiments , and quasi-experiments. Actions for Describe the similarities.
Chapter 11 Quasi-Experimental Designs ♣ ♣ Introduction   Nonequivalent Comparison Group Design   Time-Series Design   Regression Discontinuity Design.
A SYSTEM FOR CHOOSING STATISTICS u What type of design do you have? u What do you want to find out? u What type of data do you have?
Quasi-Experimental Designs Whenever it is not possible to establish cause-and-effect relations because there is not complete control over the variables.
Nasih Jaber Ali Scientific and disciplined inquiry is an orderly process, involving: problem Recognition and identification of a topic to.
Problem identification Research questions Constructs & Variables Research design.
METHODS IN BEHAVIORAL RESEARCH NINTH EDITION PAUL C. COZBY Copyright © 2007 The McGraw-Hill Companies, Inc.
Quantitative Research Designs
SINGLE - CASE, QUASI-EXPERIMENT, AND DEVELOPMENT RESEARCH © 2012 The McGraw-Hill Companies, Inc.
1)Test the effects of IV on DV 2)Protects against threats to internal validity Internal Validity – Control through Experimental Design Chapter 10 – Lecture.
Correlational Designs
Copyright © 2007 by The McGraw-Hill Companies, Inc. All rights reserved. Chapter 3 The Research Endeavor.
COMM 250 Agenda - Week 10 Housekeeping C2 – Returned to You Today RP1 – Due Today (IM Surveys) TP3a – Due Tomorrow Lecture RAT4 Review RP1 Experiments.
Group Quantitative Designs First, let us consider how one chooses a design. There is no easy formula for choice of design. The choice of a design should.
1 Experimental Research Cause + Effect Manipulation Control.
Chapter 3 should describe what will be done to answer the research question(s), describe how it will be done and justify the research design, and explain.
Quantitative Research SPED 500 Dr. Sandra Beyda Designs that maximize objectivity by using numbers, statistics, structure, and experimenter control Modes.
It gives reliable and systematic ways to answer psychological questions like: How do I analyze dreams? Why are boys so weird? Other sources of info like.
Chapter 10 Finding Relationships Among Variables: Non-Experimental Research.
Ex Post Facto research Researcher cannot manipulate some variables and therefor selects participants that have certain values for those variables by themselves.
Copyright © 2011 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Using Specialized Research Designs.
SINGLE - CASE, QUASI-EXPERIMENT, AND DEVELOPMENTAL RESEARCH.
12 ©2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Nonexperimental and Quasi- Experimental Designs Distinction is the degree of control over internal validity.
Research Design. Time of Data Collection Longitudinal Longitudinal –Panel study –Trend study –Cohort study Cross-sectional Cross-sectional.
Chapter 11.  The general plan for carrying out a study where the independent variable is changed  Determines the internal validity  Should provide.
SOCW 671: #6 Research Designs Review for 1 st Quiz.
Slides to accompany Weathington, Cunningham & Pittenger (2010), Chapter 15: Single-Participant Experiments, Longitudinal Studies, and Quasi-Experimental.
Types of Experimental Designs (Educational research) True Experimental Quasi-Experimental.
Non-Experimental designs Psych 231: Research Methods in Psychology.
Varieties of Research Designs 3x3 Structure for single-IV designs –(3) Design differences & causal interpretability –(3) Design differences & statistical.
©2005, Pearson Education/Prentice Hall CHAPTER 6 Nonexperimental Strategies.
1. /32  A quasi-experimental design is one that looks like an experimental design but lacks the key ingredient -- random assignment. 2.
William M. Trochim James P. Donnelly Kanika Arora 8 Introduction to Design.
Chapter 9 Scrutinizing Quantitative Research Design.
Experimental Research Designs. Experimental Design Advantages  Best establishes cause-and-effect relationships Disadvantages  Artificiality of experiments.
Correlational Designs Causal Modeling Quasi-Experimental Designs.
Quasi-Experiments. Quasi-Experiment Involves the comparison of pre-defined groups.
Practical Research: Planning and Design, Ninth Edition Paul D. Leedy and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All rights reserved. 1 Chapter.
CHAPTER 13: THE NUTS AND BOLTS OF QUASI- EXPERIMENTS.
Experimental and Quasi-Experimental Research
The Non-Experimental and Quasi- Experimental Strategies:
Experimental Research Designs
تحقیق علّی – مقایسه ای به نام خدا عنوان: Causal-Comparative Studies
Group Quantitative Designs
Designing an Experiment
Scientific Method Attitude Process
The Nonexperimental and Quasi-Experimental Strategies
Types of Designs: R: Random Assignment of subjects to groups
Presentation transcript:

QUASI-EXPERIMENTS What is a Quasi-Experiment? What is a Single-Group Time Series Design? Why Do Quasi-Experiments? What is a Multiple-Group Time Series Design? What is an Ex Post Facto Design? What is a Cross-Sectional Design? What is a Single-Group Posttest Only Design? What is a Longitudinal Design? What is a Single-Group Pretest/Posttest Design? What is a Sequential or Cohort Design? What is a Nonequivalent Control Group Pretest/Posttest Design? How Are Quasi-Experiments Analyzed?

What is a Quasi-Experiment? Compare subjects in different conditions on a DV Lacks one or more criteria for an experiment (cause, comparison, control) Interpreted like a correlational study

Why Do Quasi-Experiments? Internal validity is a problem because the IV is not manipulated It may not be possible or ethical to manipulate the IV

What is an Ex Post Facto Design? Compare groups that differ on a pre-existing variable (subject variable) Examples: gender personality presence of mental disorder

What is a Single-Group Posttest Only Design? Scores are measured after a treatment for one group The treatment is not manipulated, and there is no comparison

What is a Single-Group Pretest-Posttest Design? Scores are measured before and after an event or treatment The treatment is not manipulated

What is a Non-Equivalent Control Group Pretest/Posttest Design? Compare a treatment group and a control group before and after the treatment The groups are not randomly assigned

What is a Single-Group Time Series Design? Scores are measured several times before and after an event or treatment Better than Pretest-Posttest design, because you can tell whether the change is likely to be due to a random fluctuation

What is a Multiple-Group Time Series Design? Scores for a treatment and control group are measured several times before and after The control group is not randomly assigned Combination of Nonequivalent Control Group and Interrupted Time Series

What is a Cross-Sectional Design? Compare different age groups at one point in time The groups may differ on other variables, since age is not manipulated cohort effects - generational history differences

What is a Longitudinal Design? Measure the same group at different ages Time-consuming Attrition can be a problem

What is a Sequential or Cohort Design? Compare different age groups at different ages Combination of longitudinal and cross-sectional

How Are Quasi-Experiments Analyzed? Choose from the same set of statistics used for experiments Remember that you interpret differences like the study was correlational Take into account number of conditions and whether variables are between or within subjects