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 • e.g., avoid or minimize pain and discomfort • Institutional Review Board (IRB) • reviews research protocols for studies using human participants • primary concern is participant welfare • has informed consent been obtained? • do potential benefits of study outweigh risks to participants?

3. Research Participants • Chosen participants depends on research question • obtaining animals • albino variant of brown rat is most commonly used • the Animal Welfare Act regulates care and housing • the Guide for the Care and Use of Laboratory Animals (1996) provides a guide to using animals appropriately

4. Research Participants • Obtaining human participants • recruitment depends on type of participant needed • examples • research question dictates homeless participants then you would contact homeless shelters and visit areas frequented by homeless individuals • research question dictates school children as participants then you would contact schools and possibly pediatricians’ offices • convenience sample of college students often used in psychological research • may not be representative of target population

5. Research Participants • Obtaining human participants • using the Internet to recruit research participants is becoming more common • advantage • providing access to a larger and more diverse sample than otherwise possible • disadvantage • select groups may not have access to Internet (e.g., disabled) • sample may not be representative of target population • No matter how participants are recruited • important to report how participants were selected and assigned to research conditions (methods section)

6. Sample Size • How many research participants should be included in the research? • practicality must be balanced with the increased power that accompanies a large sample

7. Power • The probability of correctly rejecting the null hypothesis • Correctly saying the treatment conditioned produced an effect • Power of at least .80 is desired • i.e., we want to correctly reject a false null 80% of the time • Factors that influence power • sample size • as sample size increases, power increases • so does time and money required to complete research • alpha level • for now, all you need to know is that alpha is set at 0.05 • effect size • the magnitude of the relationship between two variables in a population • can be estimated at small, medium, and large • examine literature for approximate effect size estimation • Should conduct Power Analysis to estimate sample size

8. Power Analysis

9. Apparatus and/or Instruments • How will independent variable be manipulated and how will dependent variable be measured? • depends on nature of research • may involve active participation by researcher • example – Langhinrichsen-Rohling and Turner (2012) • a particular type of apparatus • examples – computers, MRI, EEG • Behavioral Research Methods is a good source to identify research instruments

10. Procedure and Scheduling • Procedure • detailed description of how experiment will be conducted • important to allow for future replication • Scheduling of research participants • availability of the researcher and participants • anticipate drop out rates with human participants

11. Consent to Participate • Informed consent necessary unless waived by IRB • Consent form should include the following elements: • basic information about the study • details about procedure of study including possible risks • any potential benefits that might be derived • the type of compensation provided and compensation penalty for early withdrawal • for sensitive topics (e.g., depression, abuse) extra information for individuals who need assistance • participants must be informed that they can withdraw from study at any time without penalty • if using questionnaire, a statement indicating that participant can refuse to answer any question without penalty • participants must be informed as to how the records and data obtained will be kept confidential

12. Instructions and Data Collection • Instructions • should be precise, but not overly complex • refrain from certain phrases • “pay attention”, “relax”, and “ignore distractions” • language should be simple and on the level of the participant • warm-up trials can assess understanding of instructions • Data collection • follow design

13. Debriefing • Functions • ethical • undo any deception involved in study • decrease stress or risk if possible • attempt to return participants to pre-experimental state • particularly important if deception is used • educational • this mostly applies to students participating in research for class credit • methodological • to establish effectiveness of independent variable or deception • to judge accuracy of participations’ suspicions and perceptions • sense of satisfaction • participant feeling as if they contributed to science and society

14. Debriefing • 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 • 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

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