FAQs for Internal Assessment

The following page provides answers to commonly asked questions about the internal assessment. 

As more questions arise in the new curriculum, more questions and answers may be added to this page.

What is meant by a simple experiment?

The psychology course defines a simple experimental study as requiring the manipulation of one independent variable and measurement of one dependent variable, while other variables are kept constant. Consequently, correlational studies, quasi-experiments and natural experiments (that is, any research undertaken without control over the independent variable and without a controlled sampling procedure) are not acceptable for the simple experimental study.

May students do a comparison of gender differences?

Variables that are based upon pre-existing characteristics of the participants are not suitable for the IB Internal Assessment. Variables that are not acceptable independent variables include, but are not limited to:

  • gender (e.g., comparing the results of female and male participants)
  • age (e.g., the performance of 10 year old participants as compared to 18 year old participants)
  • native language (e.g., native French speakers versus native Mandarin speakers)
  • culture (e.g., Afro-Caribbean participant results as compared to Swedish participants)
  • education level (e.g., students in grade 5 as compared to students in grade 11)
  • socio-economic status (e.g., poor participants versus rich participants)
  • handedness (e.g., left-handed and right-handed participants)

While these variables might be of interest to students, they cannot be manipulated within the framework of the IA. Studies submitted for internal assessment that does not meet the requirements for experimental work will be awarded zero marks.

What is the difference between the SL and HL IA?

There is no difference between HL and SL as of May 2019.

How large a sample must students have?

Students should strive for 20 participants in their study - that is, two groups of 10 or one group of 20.  Fewer than 10 in a group makes it very difficult to have valid statistical analysis. Students may pool data with other students in order to get the minimum sample size.

Must students work in groups?

Yes.  As of May 2019, all IAs must be the product of group work. If there are no other candidates in the school, the IB recommends remote sharing of data with students at another school. A group must have a minimum of two students and up to four students.

Each group must collect its own data. More than one group is allowed to research the same hypotheses (HL) or aims (SL), but each student must write up his or her own individual report. It is accepted that the procedures, data tables and materials of a group working together will be identical.

Are there any other limitations on what they may do?

Examples of experiments that are unacceptable for HL or SL internal assessment include:

  • Conformity and obedience studies
  • animal research
  • placebo experiments
  • experiments involving ingestion (e.g., food, drink, smoking, drugs)
  • experiments involving deprivation (e.g. sleep, food)

In addition, students may not use small children in their sample.  It is recommended that no one under the age of 16 would be used in the sample.

Do students need to cite the original study?

No. Students may find the study to be replicated in any text, as long as they cite the text in which they find it. Students are not awarded more credit for using the original study. Often, the original study is very difficult for young psychology students to understand, so a more learner-friendly version may be more appropriate.

May students use the original materials from the study or must they create their own?

More often than not, it is not possible to find the original materials or obtain the original list.  The IB Psychology IA report requires that students justify their choice of materials.  If students are able to obtain the original materials, they may use them - but they need to justify why this choice was made. 

Must students include all calculations in the appendices?

Students are no longer required to include calculations of their descriptive statistics in the appendices.  However, they should include a print-out of how they calculated the inferential statistics.  This will assist the moderator.

May the classroom teachers give consent for their students?

No. Participants 16 and older must each fill in their own consent form. Experimental studies involving children under age 16 need the written consent of parent(s) or guardian(s). Candidates must ensure that parents are fully informed about the implications for children who take part in such research. Where an experimental study is conducted with children in a school, the written consent of the teachers concerned must also be obtained.

Is it allowed to use deception at all?

Any experimental study that involves unjustified deception must be avoided. Minor deception with regard to the goals of the experiment are allowed.

What is included in the word count? How strictly should the student follow the guidelines?

The word-count is to be strictly adhered to. Students should not assume that it is acceptable to go over the word count. Remember that the title page, appendices, graphs, tables, section headings and works cited page are not included in the final word count.

Do we need to send all materials used, including DVDs & powerpoint presentations?

Students should cite all DVD's in their works cited page; in addition, they should describe any materials used in the procedure section. They should keep all materials until grades are awarded in case there is some question about the nature of the material, but please do not send CD's or other physical (ie. non-paper) materials to your moderator.

What is meant by "operationalization of variables?"

In order for variables to be operationalized, it must be explained how the IV and DV will be measured.  Simply writing that the IV was "stress" and the DV was "accuracy" is not an operationalization of the variables.  There should be a clear explanation of how the variables will be defined and measured in the experiment.

What if my students' results are not signficant?

Hurrah!  In some ways, this makes it even easier to write the discussion!  When the experiment works perfectly, often it is difficult to write about the limitations of the study.  Students are not penalized if they do not reach the same conclusions as the original study.  The "replication" is solely of the procedure, not of the findings.

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Comments 36

Karen Hinnen 25 April 2018 - 14:20

If the original experiment utilized an Independent Measures Design, may the students alter it and use a repeated measures design? Also with a repeated measures design, may the students have 10 participants (because they are testing both conditions) or do they need 20 participants? For an Independent measures they need 20 total (10 per group because they are different individuals). Correct?

John Crane 26 April 2018 - 12:01

Dear Karen

All correct. They may change the experiment's design - and 10 is fine for repeated measures. They should, however, explain why they chose this other design when replicating the study. This would go into their "exploration" section of the report.

Karen Hinnen 27 April 2018 - 19:29

One additional question. One of my groups wants to replicate the Craik and Tulving Depth of Processing experiment. The conditions are phonetic, structural and semantic. In the original experiment they asked questions to determine whether the question rhymed with ___ or if it was in capital letters or if it fit in the sentence etc. Then there was a "surprise" recall test. Does this meet the parameters of our experiment? The students are presenting all of the words at the same time (no separate groups or times). I guess it is a repeated measures design, but all at the same time??? Opinions on this...

John Crane 28 April 2018 - 06:02

Yes, concurrent conditions are allowed by the IB. So, this is fine. But have you taught them statistics for more than two levels of the IV? If not, I would have them limit it to two conditions.

Karen Hinnen 1 May 2018 - 13:32

Thank you so much for your help John! I did instruct them to limit the study to two conditions because of the ANOVA necessary for multiple conditions.

SHILPA KAPOOR 9 May 2018 - 07:00

Dear John,

One group of my students want to do an IA on Watson's Four Card Experiment.
Do you think that would be acceptable?
Thank you for the constant help.

John Crane 9 May 2018 - 07:25

Dear Shilpa

Only if they do the Griggs version in which they have abstract vs non-abstract concepts to see if there is a difference in the rate of correct answers.

Ian Latham 10 May 2018 - 07:14

Marking 1st draft of practice IA: found a student who in their Exploration has not mentioned the briefing/debriefing. In the old marking criteria a lack of evidence of 'evidence of ethical considerations' was serious, wasn't it? Yet the new marking criteria doesn't mention that. Nor does it mention explicitly the procedure!

So if they describe the design, the sampling, the participants, standardisation of instructions and choice of materials, but do not explicitly refer to ethical considerations (ie informed consent, briefing and debriefing with option to remove data) or if they don't outline the procedure, step-by-step, they could still potentially get 2 out of 4 marks. (And if explaining, then 4 out of 4.)

Perplexed in Bcn!

John Crane 10 May 2018 - 08:10

Dear Ian

If they don't outline a procedure, they will be penalized in both exploration and evaluation, since the reader will have no idea what they actually did. The procedure is no longer discreetly assessed because it must be the same for all members of the group and it must be approved by the teacher. It seems odd to give 2 marks for something of that nature. Also, since it is often a replication, it makes very little sense to assess it. As for the ethics, if the IA lacks evidence of meeting ethical standards, it will be seen as "academic malpractice" and could earn zero marks. How that will work in practice, I do not know. But i would tell students to include all documentation of how they met ethical standards. In the past, this was seen as a mark for "compliance." This is now "passé" in education, so it has been taken out. The lack of clarity in the guide is very frustrating.

Karen Hemming 21 May 2018 - 15:47

Hi John,
Do students need justify selection of parametric vs non-parametric testing in the Analysis section? And would small sample size be enough to justify the use of a non-parametric alternative, or would students also be expected to refer to whether there is a normal distribution or not?
Thanks in advance!


John Crane 22 May 2018 - 04:59

Dear Karen

In the new IA, there is no longer a requirement to justify the statistics. It is only important that they apply appropriate statistics. And yes, small sample size is technically not enough. The lack of a set of normally distributed data would also be necessary to justify the test. However, often non-parametric tests are used for small samples without having to meet that requirement.

Alistair Booth 25 May 2018 - 10:09

HI John,
Can students use APA referencing?
Many thanks

Mamta Bashisth 19 June 2018 - 08:35

One of the group is planning to do Baddeley 1966, acoustic vs semantic with each having two condition. This will sum up to 4 conditions.



Acoustic similar

Acoustic dissimilar

Semantic similar

Semantic dissimilar

As per my understanding students can replicate all conditions but only one IV (subject guide page 52). Looking at the Baddeley study what is your take on IV, is it one or two.
To me, there are two IVs here
1. Acoustic
2. Semantic

DV- word recall

I need your guidance here, and if you have any sample from past I will love to have a look.

Thank you

John Crane 19 June 2018 - 09:36

Dear Mamta

I do not have a sample. The two IVs seem to be the level of similarity and whether it is acoustic or semantic. I would test only one of those only. So, either both acoustic both similar vs. dissimilar - or both similar but one acoustic and one semantic.

Mamta Bashisth 19 June 2018 - 10:21

Thanks John, now I need to get on convincing them. Their heart is set set upon strictly following Baddeley 1966 study.

Kathryn Blaszkiw 20 June 2018 - 13:15

Hi John, in the example IAs provided, the students have a research proposal in their appendix, is it necessary to include this?

John Crane 21 June 2018 - 05:12

Dear Kathyrn

No, it is not required. Personally, I have my own students do it to document their process.

Ranjani Ravi 11 July 2018 - 06:39

Hi John,
My students want to replicate the Glanzer and Cunitz experiment. However they want to conduct the experiment with 2 groups - the experimental group and the control group. So they plan to present 14 words to the 2 groups , however for the experimental group they want to introduce a distracting task for 30 seconds , after the words are presented and then test recall.
My question is will this amount to two IVs? One is we are testing for recency and primacy and then we are the effect of a distracting task on recall. Please guide.

John Crane 12 July 2018 - 06:35

Dear Ranjani. Students should test only for primacy or recency effect. Not both.

Ranjani Ravi 12 July 2018 - 06:45

So can we have 2 groups and check for the effect of the distracting task on recency?

John Crane 13 July 2018 - 16:07

Yes, that would be fine.

Ranjani Ravi 14 July 2018 - 09:08

Thank you John. Really appreciate the support.

Dora Ramirez 31 July 2018 - 19:11

Hi John,
Last year was my first time teaching DP. As I keep doing research and understanding the new changes I got a little confused with the following; I keep reading the changes are for students taking the may 2019 exams but for the IA it says as of may 2019. Considering that IA are handed in March 20th would the changes apply to that group of students that hand in March 2019?
Thank you so much for all the help! Year 1 would have been far much harder if I would not have had access to all these materials you post here.


John Crane 2 August 2018 - 07:31

Dear Dora,

Yes. May 2019 is the description of the "session." So, all work that candidates submit leading up to the May exams is included under that label.

Dora Ramirez 7 August 2018 - 15:01

Thank you so much :)

Jessica Brown 14 August 2018 - 05:44

Hi John,
I have students completing a replication of Glanzer and Cunitz's (1966) study. I am just having trouble with recommending what statistical analysis to run.

I am wondering whether it is enough for students to say that a delay will affect the number of words recalled or do they need to specific and say that words in the list (e.g. first and last words) were remembered better (demonstrating primacy and recency effect)? They have conducted an independent measures design. I thought a simple unrelated t test to assess a difference between the two conditions would be enough but should they be looking deeper than this? And does the statistical analysis need to be similar to the original study?

I hope that makes sense!


John Crane 15 August 2018 - 05:27

Dear Jess

They do not need to specify recency or primacy effect, but that was what the original study was looking at so it would be appropriate. Yes, an unrelated t test would be fine, or they can use the Mann Whitney. One inferential statistic is enough, but they also will need to have descriptive stats. No, they do not have to have the same stats as used in the original study.

Jessica Brown 20 August 2018 - 03:30

Hi John, this might seem like a silly question, but my students are currently working with the data they have collected and I just have a question about rounding the numbers when they are using excel - they are looking replicating Landry and Bartling so their DV measured average letter recall. I think when finding the averages before conducting t tests they should round the numbers to zero decimal places as they are working with whole letters and there is no such thing as remembering 4.3 of a list of letters - can you confirm if this is correct or should they leave the results unrounded?

Thanks again! Jess

John Crane 21 August 2018 - 05:24

Dear Jess, they should leave the numbers unrounded.

Sergio Jiménez 4 September 2018 - 20:37

Hi John, I started last year teaching IB Psychology (year 1) and I just have 8 students in my class. They are going to split in 2 groups of 4 to carry out the IA, and both groups want to replicate Loftus and Palmer´s leading questions experiment related to schema theory. Are both groups of students allowed to do the same experiment and study the same theory? Or do they have to replicate different experiments?
Thank you very much! Sergio

John Crane 5 September 2018 - 06:15

Dear Sergio

There is no rule that they may not do the same experiment, but they should have different data sets.

Jane Gallagher 27 September 2018 - 02:32

Dear John,
I have a group who want to replicate Stroop. In the past students have always compared condition 1: non conflicting ( font matches colour word) to condition 2: conflicting (the font colour and the colour word don't match). But in keeping with the original study my current group would like to change the first condition to colour names printed in black. I have never seen this done before but am hoping it is ok? Thank you very much.

John Crane 27 September 2018 - 05:01

Dear Jane

It is absolutely ok. Replicating the original study is actually encouraged.

Jennifer Casaine 1 October 2018 - 19:22

Dear John,

I know that students can pool data with another group. Just making sure that if two separate groups of 3 use the same participants, this would work. I feel as if that makes them a group of 6 researchers since using the same data requires procedures and conditions to be the same. How should I interpret the pooling part? The experiment requires one by one implementation and we're trying to be efficient.

John Crane 2 October 2018 - 05:17

Dear Jennifer,

I am not sure that I understand. The students may pool data only if they have the same standardized procedure, but each group must have their own participants. I am not clear how the two groups could have the same participants.

Jennifer Casaine 3 October 2018 - 12:59

Thank you, John. This is why I wanted to clarify the word "pool." Two or 3 separate groups can do the same exact procedure, but maybe have 6 participants each. Then for the results use the total number of participants, 18. My whole class (10 students) is doing the same study which is a first for me so I wanted to make sure this does not get confused with a group larger than the max of 4.
Thanks for your quick reply.