1. IB Psychology Internal Assessment Higher Level 20% of final grade
Standard Level
25% of final grade

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

3. IA Differences between SL and HL
Weighting: 25%
Replicate a published experimental study;
Characteristics of SL simple experimental study:
Limited in scope
Involves the manipulation of only one independent variable
Involves the measurement of only one dependent variable
Requires the use and interpretation of the descriptive statistics
Does NOT require the use of inferential statistics ;
State the aim of the study.
Weighting: 20%
HL students:
may undertake a replication or a modification of a published experimental study;
Are required to undertake more extensive background research related to their simple experimental study; 3 studies!!!
State an operationalized experimental hypothesis;
State an operationalized null hypothesis;
Apply inferential statistical test to their data and interpret the result of the test.

4. Internal Assessment CriteriaSL
A – Introduction – 2 marks
B – Method: Design – 2 marks
C – Method: Participants – 2 marks
D – Method: Procedure – 2 marks
E – Results - 4 marks
F – Discussion – 6 marks
G – Presentation – 2 marks
Total: 20 marks HL
A – Introduction – 5 marks
B – Method: Design – 2 marks
C – Method: Participants – 2 marks
D – Method: Procedure – 2 marks
E – Results: Descriptive- 2 marks
F – Results: Inferential – 3 marks
G – Discussion – 8 marks
H – Citation of sources – 2 marks
I – Report format – 2 marks
Total: 28 marks

5. Step 1: Choosing an experiment to replicate
Guidelines:
Ensure that the study has an IV that you can manipulate (not gender/age/culture) e.g. verbs, background noise.
Your experiment should be relatively easy to replicate, cognitive experiments concerning memory are best suited to the Internal Assessment.
You must clearly justify and operationalize your hypotheses.

6. Step 1: Choosing an experiment to replicate
Guidelines:
You can not deceive, harm, or ask your participants to eat or drink any substances
You are not expected to conduct a ‘perfect’ experiment
You are not allowed to replicate experiments about/using: conformity & obedience, animal research, placebo, ingestion, deprivation, young children, quasi experiments, questionnaires.

7. Step 2: Locating Sources
Try to locate a copy of the original experiment on the internet
Find at least 3 other related studies – RESEARCH!
Analyze how all of these studies relate to your experiment – look at research design, findings etc
Avoid too many internet sources. No Wikipedia!!!

8. 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!!!

9. 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

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

11. Step 4 Obtaining your sample of participants
Student body will be your target population
It is best to select an opportunity sample but you will have to justify why you did this. i.e. easier, Ppts more willing
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

12. 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 your groups!

13. 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; Room, time of day etc. Control for extraneous variables!
Note any inadvertent differences in treatment and discuss this in your report

14. 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

15. Step 7 Analyzing the Data – Descriptive Stats
Use appropriate descriptive statistics (one measure of central tendency and one measure of dispersion)
Present your data in both words and tabular form.

16. Step 8 Analyzing the Data – Inferential Stats
Use non-parametric statistical tests of significance (Mann Whitney U-test)
Your small sample size prohibits parametric tests like the t-test.
Best to calculate your test yourself but double check with online sites
Raw data and calculations should be included in the appendix

17. Which Inferential Test? HL only!!
Level of measurement
Appropriate test for independent samples
Appropriate test for repeated measures
Nominal
(Categories, frequency)
Chi-squared (X2 test)
Ordinal, Interval or Ratio
Mann-Whitney U test
Wilcoxon signed ranks test

18. Writing Your Report You MUST follow the IB guidelines.
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. Avoid the 1st person “Basically I did this, then I did…..”