Experimental Research Keith Carrington Valerie Nash Keith Nerby Kathleen Olewinski Tanya Wojciechowicz ED 740, November 2010

Experimental Research Purpose: to test cause-and- effect relationships between variables

Experimental Research Groups Experimental (Treatment) Group “participates in an intervention” (p. 226) experimented on or receives treatment Control Group“a group that receives no intervention” (p. 226) NOT experimented on and receives NO treatment Leedy, P. D., & Ormrod, J. E. (2010). Practical research. Upper Saddle, NJ: Pearson Education.

Experimental Group: receives the treatment or is experimented on Control Group: receives NO treatment; NOT experimented on Group 1 diet pill Group 2 placebo

Group 1 Sustained Silent Reading (SSR) Group 2 Reading strategy Experimental Group: receives the treatment or is experimented on Control Group: receives NO treatment; NOT experimented on

Types of Variables Independent Variable “variable that the researcher studies as a possible cause of something else -- in many cases, it is the one that the researcher directly manipulates” (p. 224) The variable that is different or changed between groups. This is often the treatment or intervention. Dependent Variable “a variable that is potentially influenced by the independent variable… and so to some extent depends on the independent variable” (p. 224) The variable that is measured or thought to be influenced by the independent variable. Confounding Variable Ways that two or more groups are or might be different in addition to the particular treatment or intervention. When you have more than one independent variable. Leedy, P. D., & Ormrod, J. E. (2010). Practical research. Upper Saddle, NJ: Pearson Education.

Independent variable: the item the researcher changed between the groups (often it is the treatment) Dependent variable: variable thought to be influenced by the independent variable (is measured or observed) Confounding variable: ways the groups might be different in addition to the independent variable Group 1 diet pill Group 2 placebo

Group 1 SSR Group 2 Reading strategy Independent variable: the item the researcher changed between the groups (often it is the treatment) Dependent variable: variable thought to be influenced by the independent variable (is measured or observed) Confounding variable: ways the groups might be different in addition to the independent variable

Controlling Confounding Variables Purpose: to maximize internal validity by ruling out confounding variables Keep some things constant Pretest to assess equivalence Include a control group Expose participants to all experimental conditions Randomly assign people to groups Statistically control for confounding variables

Leedy, Table 10.1 (pp ) Leedy, P. D., & Ormrod, J. E. (2010). Practical research. Upper Saddle, NJ: Pearson Education.

Types of Experimental Design 1. Pre-Experimental Design: “forming a tentative hypothesis that should be followed up with more controlled studies” (p. 229) 2. True Experimental Design: administering different treatments to a single group 3. Quasi-Experimental Design: considers the variables that researchers are unable to control and cannot rule out as alternative explanations for results Leedy, P. D., & Ormrod, J. E. (2010). Practical research. Upper Saddle, NJ: Pearson Education.

Ex-Post-Facto Design “after the fact” Purpose: to determine if causality exists How: the researcher “studies the possible effect of an environmental factor that has occurred prior to the study itself” (p. 228) Leedy, P. D., & Ormrod, J. E. (2010). Practical research. Upper Saddle, NJ: Pearson Education.

Meta-Analysis Combines the results of several studies

Experimental Research Issues Ethics and Integrity Responsible Conduct Informed Consent (e.g., Harmon, 2010) eekinreview/25harmon.html?_r=1 Human Subjects/ Research Participants Conflict of Interest Research Abuses IRB Approval* Publication/Peer Review Collaborative Research Cardinal Stritch University. (2010). Institutional review board. Retrieved from

Experimental Research Collaborations BenefitsChallenges Broadened experimental approach Differences in approaches Interdisciplinary; new knowledge formed Responsibility and accountability Development of new research strands Ethical issues Expertise, methodology and resources Conflicts Grants and other funding opportunities Disclosing potential conflicts of interest

Heart Monitor Experiment Research Question: Do squat jumps change instantaneous heart rate? 1.Establish and record your resting heart rate using the monitor. 2.If you are in the BLUE group, please remain seated without moving as much as possible. If you are in the ORANGE group, please do as many squat jumps as fast as possible in the time given. 3.Establish and record your heart rate using the monitor.

Heart Monitor Data Heart Rate Increased Heart Rate Decreased Heart Rate Stayed the Same Blue Group Orange Group

Please identify the following from the heart rate monitor activity. 1.Experimental Group - receives the treatment or is experimented on 2.Control Group - receives NO treatment; NOT experimented on 3.Independent variable - the item the researcher changed between the groups (often it is the treatment) 4.Dependent variable - variable thought to be influenced by the independent variable (is measured or observed) 5.Confounding variable - ways the groups might be different in addition to the independent variable

References Cardinal Stritch University. (2010). Institutional review board. Retrieved from Harmon, A. (2010, April 24). Where’d you go with my DNA? The New York Times. Retrieved from /04/25/weekinreview/25harmon.html?_r=1 Leedy, P. D., & Ormrod, J. E. (2010). Practical research: Planning and design (9 th ed.). Upper Saddle River, NJ: Pearson Education.