1. IB Psychology
Internal Assessment

2. The Task
Replicate an experiment that manipulates an Independent Variable
Write a report conforming to IB guidelines

3. Step 1: Choosing an experiment to replicate
Guidelines:
Ensure that the study has an IV that you can manipulate (not gender/age/culture)
Your research question should be important. If you can not find at least a few sentences in a standard psychology text about the research you plan to replicate, think again.
You must clearly justify your hypothesis.

4. Step 1: Choosing an experiment to replicate
Guidelines:
You cannot deceive, harm, or ask your participants to eat or drink any substances
You are not expected to conduct a ‘perfect’ experiment

5. Step 2: Locating Sources
Locate a copy of the original experiment
Find at least 5 other studies (HL)
Analyze all of these studies by breaking them down into research design elements, theory and conclusions
Avoid too many internet sources

6. Step 3 Modifying the Research Design
You will have to modify the original experiment
Sampling
Reduce the number of variables
Simplify the DV
Use a different statistical test to determine significance

7. Step 3 Modifying the Research Design cont’
Independent measures design Versus repeated measures design . (Be able to justify this in your report)
Independent measures is usually best as you do not have to undertake counterbalancing to avoid the test-retest confounding variable

8. Step 4 Obtaining your sample of participants
The ISL student body will be your target population (experiment fatigue)
Randomly sample
You can select an opportunity sample but you will have to justify why you did this
An ideal sample is 50 students giving you two groups of 25. If you have some no-shows you will still have 20 per group

9. Step 4 Obtaining your sample of participants
Signed informed consent forms must be obtained (You will provide a copy of the consent form in your appendix)
Students younger than 16 will require parental consent
You must keep all forms and ensure the confidentially of data
You must collect relevant bio-data from the participants e.g. age, first language etc. You will report any relevant characteristics
You must randomly assign participants to groups

10. Step 5 Ensuring Control
The two groups in your experiment should be treated exactly the same except for the IV
All instructions to the groups should be scripted to ensure they are identical
All other conditions should be identical as far as possible
Note any inadvertent differences in treatment and discuss in your report

11. Step 6 Ethical Considerations
Remind participants that they are free to leave the experiment at any time
Debriefing: All participants must be informed of the results of your experiment

12. Step 7 Analyzing the Data
Use non-parametric statistical tests of significance (Mann Whitney U-test)
Your small sample size prohibits parametric tests like the t-test.
Use online sites to calculate
Raw data and calculations should be included in the appendix

13. Writing Your Report
You MUST follow the IB guidelines and use APA format.
Common omissions: no abstract; data not displayed in three ways i.e. words, tables and graphs; sources not cited, no Works Sited page; no appendices (sample informed consent form, raw data, statistical test calculations, scripted instructions)
You must write like a social scientist

14. Student Advice
Do not underestimate the amount of time required to complete the IA
Do not choose a study that is too obscure
Scientific writing is “way harder” than you think
Think about the best time to hold your experiment so that students will turn up
Time management is the key
It is okay if you do not accept your hypothesis