Procedure for Conducting an Experiment

1. 9 Procedure for Conducting an Experiment

2. Institutional Approval • Institutional Animal Care and Use Committee (IACUC) • reviews research protocols for studies using nonhuman animals • determines if proposed procedures are ethical • Institutional Review Board (IRB) • reviews research with human participants • primary concern is participant welfare • has informed consent been obtained? • do potential benefits of study outweigh risks to participants? • Animals • the Animal Welfare Act regulates care and housing • the Guide for the Care and Use of Laboratory Animals provides a guide to using animals appropriately

3. Research Participants (cont'd) • Human participants • convenience sample of college students often used in psychological research • may not be representative of target population • some research requires special populations (e.g., school children) • using the Internet to recruit research participants is becoming more common • advantage of providing access to a larger and more diverse sample than otherwise possible • sample may not be representative of target population • important to report how participants were selected and assigned to research conditions

4. Power • How many research participants should be included in the research? • practicality must be balanced with the increased power that accompanies a large sample • Power– the probability of correctly rejecting null hypothesis • Power of at least .80 is desired (Reject Null 80% of the time) • As sample size increases, power increases • Factors that influence power: alpha level, sample size, and effect size • Effect size: the magnitude of the relationship between IV & DV in a population (Small, Medium, Large) • examine literature for approximate effect size estimation • Should conduct Power Analysis to estimate sample size

6. Power • Apparatus and/or Instruments • How will IV be manipulated and how will DV be measured? • depends on nature of research – may involve active participation by researcher or a particular type of apparatus (e.g., computers, MRI) • Apparatus and/or Instruments • Behavioral Research Methods, Instruments, and Computers is a good source to identify research instruments • Procedure • detailed description of how experiment will be conducted • important to allow for future replication • Scheduling of research participants • consider issues of availability and anticipate drop out rates with human participants

7. Power (cont'd) • Consent to participate • informed consent necessary unless waived by IRB • consent form should include the following elements: • basic information about the study – where it will be conducted, duration • details about procedure of study including possible risks • any potential benefits that might be derived

8. Power (cont'd) • Consent to participate • consent form should include the following elements: • the type of compensation provided and penalty for early withdrawal • if using questionnaire, a statement indicating that participant can refuse to answer any question without penalty • for sensitive topics (e.g., depression, abuse) extra information for individuals who need assistance

9. Power (cont'd) • Consent to participate • consent form should include the following elements: • participants must be informed that they can withdraw from study at any time without penalty • participants must be informed as to how the records and data obtained will be kept confidential • Instructions • should be precise but not overly complex • warmup trials can assess understanding of instructions • Data collection

10. Debriefing or Postexperimental Interview • Functions • ethical • attempt to return participants to preexperimental state; particularly important if deception is used • educational • methodological • to establish effectiveness of independent variable or deception • sense of satisfaction

11. Debriefing or Postexperimental Interview (cont'd) • Functions • sense of satisfaction • feeling in participants that their participation has been beneficial to science and society

12. Debriefing or Postexperimental Interview (cont'd) • How to debrief • face to face generally preferred • begin by asking if participant has questions • question participant to determine if all aspects of study were clear • if deception was used

13. Debriefing or Postexperimental Interview (cont'd) • How to debrief • if deception was used • attempt to determine if participant discerned true nature of study • explain the purpose of using deception • ask participant not to reveal details of experiment to other participants

14. Debriefing or Postexperimental Interview (cont'd) • Is debriefing effective? • ethical and methodological likely to be fulfilled if procedures are followed; educational less likely

15. Pilot Study • A brief run-through of the entire experiment with a few participants prior to the actual collection of data • Serves several purposes: • establishes clarity of instructions • provides evidence that independent variable is being manipulated adequately • familiarizes researcher with the procedure