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Ultimate guide to the new IB scientific investigation (2023 syllabus)

Updated: Sep 15, 2023

Three DP experimental sciences (Biology, Chemistry, and Physics) have a new syllabus starting in 2023 (first assessment in 2025), and the new Environmental Systems and Societies will begin in 2024 (first assessment in 2026). Apart from significant content and assessment updates, the new scientific investigation (formerly known as the internal assessment, or IA) also received a major facelift. If you're starting one of these courses this fall, now is a great time to start thinking about your research paper and what you can do to prepare for it. For those of you still on the old syllabus, you'll find plenty of relevant advice here as well, so stick around!

cartoon science equipment sketch

Table of Contents

Use the links below to jump to the relevant sections.

What's new?

Let's get the most obvious question out of the way first. What exactly has changed with this new assessment? Well, the most obvious difference is the name. Previously known as the internal assessment (IA), we are now calling it a scientific investigation, which is how I'll refer to it for the remainder of this article. Personally, I'm thrilled with this change since I end up spending a whole class period each year just trying to explain what the IA is and what it isn't. In case you don't know, It's an internally assessed and externally moderated experimental investigation chosen by each student for each of their science courses. Does that clear things up? No? Well, here's a handy summary video and table comparing the new and old assessments.

Summary of the new scientific investigation


Old - Internal Assessment (IA)

New - Scientific Investigation


6-12 pages

3000 words maximum

Time required

10 hours

10 hours

Number of students

Individual (group data collection allowed)

Up to 3 students (research question, analysis and conclusion must be unique for each student)

% of final grade



Assessment criteria

  • Personal engagement (2 marks)

  • Exploration (6 marks)

  • Analysis (6 marks)

  • Evaluation (6 marks)

  • Communication (4 marks)

  • Research design (6 marks)

  • Data analysis (6 marks)

  • Conclusion (6 marks)

  • Evaluation (6 marks)

Total marks




Notably, the length has been standardized to less than 3000 words. This is a positive change as the previous page limitation discouraged students from including images and graphs in their reports. It also caused issues where students would manipulate their font sizes and layouts to stay within the page limit at the cost of readability. Also note that data tables, citations, headings, etc. do not count toward the total word count.

Time required

The 10 hour timing has not changed, although it continues to be misleading for students. This allocation is meant to include the time your teacher spends explaining the investigation, time for researching, experimental time, and time to meet and discuss feedback. These all take place during the school day, of course, and if that's all you do, your report will probably fall far short of where it needs to be. In reality, the scientific investigation probably takes most students upwards of 40 hours to complete, with the vast majority of work happening outside of class. That's a major investment for a course that's only supposed to have 110-180 hours of syllabus content (for SL and HL, respectively).

students collaborating on a project smiling and having fun

Number of students

I'm not quite sure what to make of this change. The IA was always an individual assessment that could only involve shared data collection in rare cases. Now the potential for collaboration is being touted by the IB, although since students are required to have different research questions, the investigations would generally end up being very different anyway. Still, if students insist on working together (possibly because their procedures are particularly complicated or time consuming), the IB gives three examples for how collaborative investigations should be differentiated.

Each student in a group uses...

  1. …the same dependent variable but chooses to investigate the effect of a different independent variable.

  2. …the same independent variable but chooses to investigate the effect on a different dependent variable.

  3. …different data within a larger dataset or database.

Despite the potential for collaborative projects, I would generally recommend that most students stick with doing their own investigations to avoid any potential complications.

Assessment criteria

Major changes here. The "communication" criteria has been absorbed by the other sections, and the "personal engagement" marks have been removed entirely. My guess is that these assessment criteria were determined to be too subjective, something external moderators and the IB would prefer to avoid. I tend to agree, for the most part.

Also, it drives me nuts that the IB didn't take this opportunity to make each section worth 5 marks instead of 6. This would have put the total marks at 20 - the same as the final grade percentage for the scientific investigation. It's such a logic fail, and it makes it unnecessarily difficult for students to calculate their predicted grades (which we all know they do obsessively).

Below are the new assessment guidelines for each of the four major criteria. These are directly from the IB documentation, and they are the same for all science subjects.

Research design


Level descriptor


The report does not reach a standard described by the descriptors below.


• The research question is stated without context.

• Methodological considerations associated with collecting data relevant to the

research question are stated.

• The description of the methodology for collecting or selecting data lacks the detail

to allow for the investigation to be reproduced.


• The research question is outlined within a broad context.

• Methodological considerations associated with collecting relevant and sufficient

data to answer the research question are described.

• The description of the methodology for collecting or selecting data allows for the

investigation to be reproduced with few ambiguities or omissions.


• The research question is described within a specific and appropriate context.

• Methodological considerations associated with collecting relevant and sufficient

data to answer the research question are explained.

• The description of the methodology for collecting or selecting data allows for the

investigation to be reproduced.

Data analysis


Level descriptor


The report does not reach a standard described by the descriptors below.


• The recording and processing of the data is communicated but is neither clear nor


• The recording and processing of data shows limited evidence of the consideration

of uncertainties.

• Some processing of data relevant to addressing the research question is carried out

but with major omissions, inaccuracies or inconsistencies.


• The communication of the recording and processing of the data is either clear or


• The recording and processing of data shows evidence of a consideration of

uncertainties but with some significant omissions or inaccuracies.

• The processing of data relevant to addressing the research question is carried out

but with some significant omissions, inaccuracies or inconsistencies.


• The communication of the recording and processing of the data is both clear and


• The recording and processing of data shows evidence of an appropriate

consideration of uncertainties.

• The processing of data relevant to addressing the research question is carried out

appropriately and accurately.



Level descriptor


The report does not reach a standard described by the descriptors below.


• A conclusion is stated that is relevant to the research question but is not supported

by the analysis presented.

• The conclusion makes superficial comparison to the accepted scientific context.


• A conclusion is described that is relevant to the research question but is not fully

consistent with the analysis presented.

• A conclusion is described that makes some relevant comparison to the accepted

scientific context.


• A conclusion is justified that is relevant to the research question and fully consistent

with the analysis presented.

• A conclusion is justified through relevant comparison to the accepted scientific




Level descriptor


The report does not reach a standard described by the descriptors below.


• The report states generic methodological weaknesses or limitations.

• Realistic improvements to the investigation are stated.


• The report describes specific methodological weaknesses or limitations.

• Realistic improvements to the investigation that are relevant to the identified

weaknesses or limitations, are described.


• The report explains the relative impact of specific methodological weaknesses or


• Realistic improvements to the investigation, that are relevant to the identified

weaknesses or limitations, are explained.

Student with glasses conducting research on a computer in a library

Choosing a research question

Now that you understand what the scientific investigation is all about, it's time to narrow down a research question. You might think that this would be easy, but many students struggle for weeks or even months to come up with a reasonable topic for investigation.

A basic template for a research question could be:

"What is the effect of (independent variable) on (dependent variable) in (test subject or condition)?"

Here are two examples:

  1. What is the effect of acidic soil pH on the mass of tomatoes grown in planters?

  2. What is the effect of different oil-based lubricants on the coefficient of friction of skateboard bearings?

Aside from the basic format of your research question, here are some additional tips to get you on the right track:

  • Make sure your research question identifies both the independent and dependent variables. Be as specific as you can (include measurement quantities, species names, etc.), even if starts to sound kind of ridiculous.

  • Choose a dependent variable that is easily measurable and provides reliable quantitative data. Recall that quantitative data is numerical, as opposed to qualitative data which is descriptive.

  • Avoid doing any of the prescribed practicals, including closely related experiments. Neither your teacher nor external moderators will be impressed by your ability to carry out an experiment that you would be required to perform anyway.

  • Don't try to be too original. Aside from the prescribed practicals, everything else is fair game. Just make sure that you don't have the same research question as another student in your class. You can always tweak a familiar experiment to make it more interesting or unique.

  • Choose a simple experiment. It's better to do a thorough job on something you understand rather than trying to impress people with a complex investigation you can't handle.

  • Choose a topic you care about. It's always easier to stay motivated when you actually care about the outcome. If you need ideas, try flipping through the textbook to find topics that you enjoyed learning about in class. Then seek ideas related to those topics.

  • Consider your timeline. When is the investigation due? If you have only a few weeks, you probably shouldn't plan to grow plants or something similarly time consuming. Also, remember that the experiment itself is only a small portion of the investigation. Give yourself enough time for research, writing, analysis, and feedback.

Types of investigations

Below are the five types of explorations the IB considers acceptable for the scientific investigation:

  1. Hands-on practical laboratory work

  2. Fieldwork

  3. Use of a spreadsheet for analysis and modelling

  4. Extraction and analysis of data from a database

  5. Use of a simulation.

The majority of students will perform a hands-on practical experiment, either in the lab or in the field. A simulation could potentially be used, but it is considered an inferior form of experimentation since it is based on many assumptions and models of real-world conditions. A student can justify the use of a simulation in cases where it would be too time-consuming or expensive to perform the experiment for real. It can also be used as a part of a larger investigation.

The use of a spreadsheet is pretty much expected for all data-based investigations, so I wouldn't count that as a separate type of investigation.

The final type of investigation would be a pure data analysis (or meta analysis). In this case, the student doesn't actually carry out an experiment themselves, but instead collects data from a variety of sources to investigate their research question. As with simulations, this is generally considered inferior to hands-on experimentation unless the student is very good at statistics and has access to a LOT of data. This type of investigation was more acceptable during the distance learning period associated with the pandemic, but now that face-to-face learning has mostly resumed, I would avoid this type of investigation under most circumstances.

female student looking through a microscope in a white science lab

Proposals and preliminary experiments

Once you have a research question and a basic plan for your investigation, the next step would be to run it by your teacher to identify any potential problems. This might seem annoying, but you really don't want to find out that your research question is flawed after you've invested hours of your time (and sometimes money).

If your plan has been approved but you still aren't sure how to proceed, it's time to perform some preliminary experiments. Doing a few informal trials will help you quickly identify problems with your variables and what quantities you should use for your actual experiment. It will also assist you in writing the procedure for your formal investigation. The good news about these preliminary experiments is that you don't have to record much. It's usually enough to simply state that you used them to inform your planning.


Next up is the research phase. Depending on your topic, this may be done before, after, or during the other parts of your investigation, but ideally, your research should continue throughout the scientific process as you identify new problems and ideas to explore.

Your research will roughly break down into three stages, as follows:

  1. Initial research - This includes any searches you do to help generate a research question or figure out what your variables might be. It should also include a brief look through existing research to see how much literature exists on your chosen topic. If you can't find much in the way of resources, it could mean a few things. It's possible that your research question is very original, in which case you will have a difficult time comparing it to other studies or supporting your findings with evidence. Unfortunately, the most likely alternative is that your research question isn't very good, which is why no one else has attempted it before. Don't feel discouraged if you find many experiments that sound just like what you are planning to do. This is a good thing, as it means you have a lot of material to work with! Once you are finished with the initial research, you are most likely ready to write your introduction.

  2. Background research - This is meant to include everything you and your intended readers will need to know in order to complete or understand your investigation successfully. It is likely to be the most extensive research you perform, and the relevant sections of your report content should reflect that. For many investigations, this ends up being 1-3 pages in length. You will need to define new terminology, explain concepts and theories, and refer to existing studies. You will also need to use your background research to inform your procedure and explain your assumptions for the experimental portion of the investigation. Sometimes while conducting background research you will stumble upon an article or experiment that is a perfect match for the topic you are exploring. That's great, but don't rely too much on a single source! Keep exploring until you have a variety of studies and perspectives to work with. When your background research is finished, you can begin writing the procedure and then carry out your experiment.

  3. Evaluative research - At this point, you've completed your experiment, made the necessary measurements, and performed a detailed data analysis. Unfortunately, you haven't explained anything yet. That's what evaluative research is for. You'll need to delve back into the literature (in some cases using the same sources you identified earlier) in an attempt to explain the patterns and peculiarities in your data. This research is straightforward because you know what you're looking for, but it's also difficult because you might not find the answers. That's just the reality of science! It's ok if you can't explain everything you observed in your analysis, but you should at least be able to offer suggestions based on your findings.

high school student in green sweater writing in notebook

Writing the investigation

The design portion of the scientific investigation comes first and includes the introduction, background research, hypothesis, variables, materials, and procedure. Following experimentation, you can then proceed to include the data analysis, conclusions, and evaluation sections. It sounds extensive, but if you take your time and follow along with the recommendations below, it's actually fairly straightforward. Let's go through each section in a bit more detail.


The introduction for the scientific investigation should include several pieces of information. Firstly, you should introduce your topic, including why you chose it and why it is important to you. If you can, identify the purpose of the investigation by linking your research question to a real-world problem or issue. It may be worth providing some facts or figures here for context. Next, briefly describe the procedure you will use in a sentence or two, along with some justification for why you chose this method. Conclude the introduction with a statement about what you hope to learn through this investigation.

Background research

See the research section described above.


State the null and alternative hypotheses in the clearest, simplest way possible. You shouldn't need more than a sentence for each of them. You might recall that the alternative hypothesis is the relationship you are expecting to observe, while the null hypothesis is that there is no relationship between your variables. Use your research question to help you construct the hypothesis, and be sure to include a scientific explanation for the relationship as well.


This section is more of a list than a paragraph, but it is still quite important. Simply state your independent variable (the one you will modify) and dependent variable (the one you will measure). Include the units you will use for those variables as well. Note that you should have just one independent and one dependent variable. There are rare exceptions to this, but that's a good general rule to follow.

After that, make a list of all the controlled variables for your investigation, which should include as many as you can think of. If you have a long list of variables, you may want to format them in a table for clarity.

chemistry glassware filled with rose coloured liquid on a white background


This is perhaps the easiest section in the entire report, but there are some details that students often forget to include. For starters, make a list of every item you will need to complete the investigation. You should be as specific as you can, including the quantities, sizes, brands, and model numbers of all equipment used. You do NOT need to include yourself or anyone who helped you perform the investigation, but you should include anyone who was a participant or test subject. For privacy reasons, however, do not use any names or identifying features. All chemicals used for the investigation should be listed here, with the exception of water, which is assumed to be freely and readily available to anyone.

Safety and ethical concerns

Apart from the materials themselves, there are some other things you should add to this part of the report if you want to receive top marks. One of these is a description of the safety and ethical concerns. If you think there are no major concerns worth mentioning, write that! For this particular section, pretend your audience is really stupid. Advise them not to eat or drink anything while doing the experiment. Remind them to wear gloves, goggles, and a lab coat if necessary. Tell them how to dispose of waste properly. The IB will expect to see something here, so don't disappoint them.


Another section that can often be found just prior to the materials list is a description of the assumptions made during the design and planning process. This will give you a chance to explain your choices for the upcoming materials list and procedure which might be hard to figure out without some context. It may also include equations or references used in the procedure. If you used people as test subjects, describe how they were selected and what they were told. Now is also a good time to justify the number of trials and conditions tested in the procedure.


I've seen students write this section in paragraphs, but I would advise against that. Instead, treat it like a recipe, with short, numbered steps and clear commands. Be specific so there's no room for error. Have a few friends read it to make sure they can understand the process. Particularly complicated procedures are best accompanied by diagrams or photographs of the experimental setup.

It used to be a big no-no to include personal pronouns in a scientific investigation, but the stance on this is has become more relaxed in recent years. Still, some teachers and moderators may look down on informal writing styles, so why risk it?

blue bar and pie graphs on a computer with a white background

Data and analysis

The data from your experiment should be organized in tables, including units and appropriate titles. If there is a lot of raw data that would take up a page or more, create an appendix for it and include only a summary table in the main report. Such a table would contain mostly totals and averages that could be used to create graphs, not individual data points.

Create your graphs using Excel and make sure you choose the correct type to represent your data. If you want to show how something changes over time, a line graph is probably best. For visualizing the relationship between two variables, a scatter plot will be most appropriate. Many students don't realize how much Excel is capable of and will not take the time to customize their graphs. Be sure to include descriptive titles, axis labels, units, and a legend (where appropriate). Trend lines and error bars should also be included, both of which can be added automatically with just a few clicks. Error bars in particular are often overlooked, but they provide useful insights for analysis.

Any equations or statistical tests used in the analysis should be shared here. Sample calculations are worthwhile too, except for very simple operations such as determining a mean value.

The last part of the analysis should be one or more descriptive paragraphs outlining the major trends in the data. This might include correlation and regression, ranges, min/max values, % increase/decrease, outliers, statistical significance, and so on. For now, your goal is simply to identify anything that might be important using your own numerical evidence. Don't attempt to explain any of your findings just yet. That will come later.

Discussion and conclusion

By this point many students are running out of steam and often rush to the conclusion without including a proper discussion. Don't make this mistake. You should absolutely report whether or not your hypothesis was supported (even partially), but be very careful with your wording here. The hypothesis should never be "confirmed" or "proven" because science doesn't deal in certainties. At best, your experiment may suggest a correlation between variables. If the data is inconclusive, state that.

I should take a moment here to discuss so-called "failed" experiments. Many students panic when their data yields no obvious relationships or their hypothesis is rejected. Let me reassure you that you cannot be deducted marks for this. In fact, this happens more often than not in science and you should not feel bad about it or attempt to cover it up with fancy or deceptive language.

The rest of the discussion should be your attempt to explain the trends you identified in the data analysis using research and logic. This is where that evaluative research I mentioned earlier comes into play. Don't be afraid to admit that you can't explain something. That's not at all uncommon. In almost all cases, you should mention that further research and experimentation should be conducted, and you can be as descriptive as you like in what that might entail.

The final paragraph of this section should mirror the introduction, so refer back to that for guidance on how to proceed. You should reflect on your stated purpose and the extent to which you have answered your research question. You should also make a statement about how your findings could potentially be applied to real-world problems or situations.

science equipment bird's eye view on wooden table


This section is meant to be an honest evaluation of your methodology, not the results of your experiment. Focus on specific problems and limitations instead of generic ones like insufficient sample size or measurement error. You should also comment on the relative effect your investigation's weaknesses may have had on the results, with justification. Was the problem significant, moderate, small, or negligible, and why?

For each area of concern you identify in the evaluation, you must also provide realistic solutions. Many students prefer to present their evaluation in table format, and I tend to agree that this makes for improved clarity.


It should go without saying that you must properly cite your sources for all facts and figures utilized in your investigation. The IB makes no recommendations as to the citation style of the scientific investigation, so just use whatever standard format your school requires. If in doubt, APA is very common among the sciences. Make use of in-text references or footnotes, depending on the format you choose. The important thing is to be consistent.

Use of AI

Surprisingly, the IB issued a recent statement regarding the approved use of AI in their assessments, including ChatGPT. They do not, however, consider content generated with AI to be the student's own work, meaning that you must paraphrase and cite AI images and text as you would any other source. Also, keep in mind that the information ChatGPT and other platforms provide may be highly inaccurate or entirely false. Proceed with caution, but don't be afraid to put AI to work to help you structure your investigation or analyze your text.


A table of contents and cover page are not required, and you should ensure that your name, school, and other identifying details are not included anywhere in your report. The entire investigation should be single-spaced, and although it isn't a strict requirement, 12-point Times New Roman font is fairly standard.

math teacher crossing arms in front of a green chalkboard covered with equations

Role of the teacher

Your teacher is there to support you with your investigation, so by all means take advantage of their guidance when necessary. Generally teachers will assess one draft version of your report and provide detailed written or verbal feedback, but you can always ask for further assistance. Just keep in mind that you are one of many students and that their time is limited.


Phew! If you made it this far, you've probably gathered more than enough information to get you on the right track for your scientific investigation. The 2025 syllabus is still very new and there simply isn't a lot of quality information out there yet, but I hope you found this article informative. Good luck!

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