How simple could an IA research question be?

Friday 2 October 2015

In a recent discussion about IA investigations I found myself defending the idea that we should encourage students to do an investigation which is suitably complex for IB Biology. The key question is, "Should we discourage students from over simplistic experiments?" If so, "Why? Where will they loose marks?"

An over simplistic experiment, in my view, is one that has no real purpose. The research question might be clear, but the answer to this question is self evident or pretty useless. Here are a couple of examples:
  • Finding the osmotic potential of onion cells, with a RQ, 'what is the osmotic potential of an onion cell?'
  • Investigating amylase using starch and iodine, RQ, 'what is the effect of temperature on amylase?"

What would be the consequence to a student who chose something really simple like this?

I looked through the OCC for supporting evidence and I estimated the maximum grades which would be possible for a very simple piece of work using an IA Investigation - marking sheet

We don't know what the grade boundaries will be yet and applying the mark scheme is still a bit of an art for us all so please take the following notes with a pinch of salt. Do leave a comment if you agree, or disagree about something.

In the frequently asked questions page on the OCC there are some useful responses.

  • It is unlikely that investigation will be totally original, but the idea should be new to the student and not simply a copy of something that has already been done in class.
  • Students can help each other, as an extra pair of hands but can't use the same data
  • Investigations using simple familiar equipment is OK but not a simple expt design: "it is expected that the level of sophistication will be commensurate with diploma level science"
  • teacher's must consult with students during the planning pocess to avoid investigations which collect no results, but a limited results set should not have a very negative impact on the student's mark.

The TSM of the OCC has some advice on the different strands of IA assessment from which I have summarised a few points below together with a comment about marking such an investigation. The Inthinking page links contain a short summary of each aspect of assessment of the Investigation.

Personal Engagement

The TSM states "The topic chosen should also be of suitable complexity. If the research question is very basic or the answer self-evident then there is little opportunity to gain full marks for exploration and analysis as the student will not have the opportunity to demonstrate his or her skills."


Students must demonstrate the thinking behind their ideas using their subject knowledge. In order to demonstrate focus on the issues at hand.…data must be of sufficient quantity and treatable in an appropriate manner, so that it can generate a conclusion, in order to fulfill the criteria of analysis and evaluation.

An experiment which was too simple or superficial would limit marks in Exploration: the aspect “topic and research question” could not be more than 4, “background information provided” might be 4 and it would probably limit, “Appropriateness of the methodology” mark to 4. This might cap Exploration to a maximum possible mark of 4.


If there is insufficient data then any treatment will be superficial - students should revisit the method before the analysis is arrived at. Alternatively, the use of databases or simulations to provide sufficient material for analysis could help in such situations.

Any treatment of the data must be appropriate to the focus of the investigation in an attempt to answer the research question.

An experiment which was too simple which didn’t have a focussed research question couldn’t really have raw data better than ‘relevant but incomplete’ = 4, Processing couldn’t be “appropriate and sufficient”. This might limit Analysis to <=4.


In the analysis, it may be concluded that there is a positive correlation between x and y; in the evaluation, the student is expected to decide, “Does the conclusion support the original thinking?”

An experiment which is too simple could not have a 4 mark conclusion “relevant to the research question” but it might have a good comparison to theory mark, and also for the strengths weaknesses and improvement suggestions. So evaluations marks would be less affected. Lets be generous and say 5 marks is possible.


This section is likely to be unaffected by the design of the experiment as it mainly depends on the formal presentation of the report

So to answer the question, "How simple could an IA research question be?"

Yes quite simple if ...

If a student is struggling to achive a grade 4 then a safe simple experiment is a good idea, so long as it meets these criteria.

  • The IA should be something new to the student, and not a repeat of something that has been done in class.
  • It must collect data either from an experiment or a data base / simulation or both.

Using guessology (in the absence of data) a very simple IA investigation could achieve the following marks: perhaps grade 5.









Personal Engagement








Not too simple, it needs some complexity if ...

If students are aiming for higher grades then something more complex is necessary otherwise the student will not be able to achieve the higher grades in exploration analysis and evaluation for the reasons outlined above.

These investigations must have:

  • a focussed research question which allows a conclusion
  • sufficient data for analysis and enough to answer the research question
  • a conclusion relevent to the research question.

I'd be really keen to know what other IB teachers think? Please leave a comment below.

Comments 3

Trevor Lafferty 9 August 2018 - 20:59

I too, have had concerns about this. For the past few years I have been encouraging students to perform experiments using multiple samples. A rough example would be... determine if X (pH) affects Y (enzyme reaction). Students perform the experiment for catalase (from two different sources e.g. potato and liver). They then analyse and compare the data from the two different sources- thus, hopefully providing the desired complexity.
However, we have not really been seeing any great improvement in the grades received and I am concerned that I am putting them through 'extra hoops' for little or no benefit. I would be grateful for any comments or ideas!

David Faure 10 August 2018 - 08:35

Dear Trevor,
Thanks for your question. I think one of the important, and quite difficult to grasp, aspects of the IA is 'appropriateness of the methodology'. Many students seem to write up the whole IA without really understanding some key aspect of how the method helps to answer the research question. Perhaps this comes from IA's which students haven't devised themselves, and in which they have missed an important logical detail. (I know it is difficult getting a whole class of students to think of their own original IA! )
Using your example of two sources of an enzyme, catalase, and the effects of pH. Here there are really two independent variables, source and pH. This increases the complexity, but it makes writing the RQn, explaining the background, analysing the data, etc. more difficult, and it doesn't help the focus of the IA or the student’s understanding the methodology. In the IA rubric there are no marks for complexity, but there are lots of marks for biological background, RQn, analysis and methodology.
I would recommend strictly keeping to a focused research question, with just one IV and one DV and encourage the student to spend more time thinking of the biological reasons which might explain the differences and adding them in the background, and the analysis. This will help their understanding of the IA they are doing, and score more highly on Ex. and Ev.
If you want to stretch the able students, get them thinking why would carrots have more or less catalase in their cells than potatoes? Why do cells have catalase in them? Would organic carrots have more or less? Is there a genetic cause? Are the catalase molecules identical in both places? Could you find out in a genome database, or in a protein database? Can you promote the production of catalase in a carrot by growing it in certain conditions?
I hope these ideas help a little. I could have said more, but there is not really enough space here for that.
Best wishes, David

Trevor Lafferty 15 August 2018 - 20:24

Thank you David, this helped to clarify things.

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