Paper 2A - Data analysis help sheet.  What will you be asked to do?

IB Better website gives these tips for Databased Questions

Don’t like the Data Based Questions?

You’re not alone!

The IB Biology Data Based Questions make up 20% of the paper 2 marks available.

But, if you’re like most other IB students, you absolutely hate the IB Biology Data Based Questions.

The myth goes that there’s simply no way to get good at these questions.

Heres a tip: don’t listen to myths. 

In this blog post, we break down all the different types of questions that get asked in the Paper 2 Data-Based Questions, to give you a massive advantage over all the other candidates. 

We will break down how to answer the following types of questions that are unique to DBQs.

1. State/Identify 

2. Calculate 

3. Outline/Describe

4. Compare and Contrast/ Distinguish

5. Evaluate Questions

General tips

1. Imagine the examiner is 5 years old and doesn’t have time for anything. The reason being that in order to gain marks you need the examiners to pick up on your points, which therefore needs to be as easy as possible. A good general tip is to make sure every sentence addresses 1 key point in the question.

2. Give as many points as there are marks available. When the question asks you to describe the graph above (3), there are 3 available marks, you should describe 3 different aspects of the graph.

3. Strongest points first! When you’re asked to describe/ compare and contrast/ evaluate data, the examiner is looking to quickly be able to give you your marks. Therefore, don’t make them read through loads of text before you get to the main points, sadly there’s a chance they’ll never read them if they don’t think you know what you’re talking about

4. Each question builds on the previous. Which means that you should avoid repeating yourself if you can. Often the questions first ask you to describe a graph, then evaluate it. It is tempting to include a description of the graph in your evaluation, but try to come up with new points if you can, they’re more likely to be on the mark schemes.

State Questions

Data Based Questions usually start with a straight forward “state” question. 

These are typically the easiest questions on the paper, because all you have to do is identify a value from the graph without doing any sort of interpretation or calculation (usually). 

The aim of these questions is for the IB to know that you are able to correctly read a graph and interpret its data.

Typically, these questions ask you to do one of the following:

– State the maximum value

– State the minimum value

The only important thing to remember is that you always need to include units.

Example:

Question: State the highest lipid content achieved by any group in the graph above.

Answer: 198 mg/g, dry cell weight.

Calculate Questions 

Calculation questions are also easy, as the math itself does not require complex arithmetic.

Usually, these questions ask the candidate (you) to subtract 2 values, add 2 values or determine the percentage difference. 

I’m going to assume that you’re quite good at subtracting and adding values, but percentage increase/decrease can muddle some students up so lets go through an example from a past exam paper: 

Using the data from the table, calculate the percentage difference in mean bird mass for the hermit thrushes refueling at Site 1 compared to those refueling at Site 2 

For copyright reasons I cant include the graph itself, so I’ll just give you the two mean bird mass values for the hermit thrushes at the two refueling sites: 

Site 1 mean bird mass: 29.8 

Site 2 mean bird mass: 28.3 

To calculate the two percentage difference:

1. Â Find the difference in mass: 29.8-28.3. 

2. Â Express the difference in mass as a fraction over the first value: 1.6 / 29.9 

3. Â Turn this Fraction into a percentage: 1.6/29.9 –> 5.3%

*** Your denominator when calculating and increase/decrease should always be the original value. So if its about the increase from January 18 to February 18, the denominator will be the January value whereas if you’re calculating the increase from February 18 to January 19 the denominator will be the February value. 

 Outline / Describe Questions

These questions usually ask you to describe some aspect of given data or a graph.

There are a few different aspects of the data you could usually be asked to outline.

Let’s go through the most common types of questions:

 1. Trends/Relationships. These are always a correlation, which can either positive (when one variable increases so does the other) or negative (when one value increases, the other decreases).

 2. Effects: Describe the specific response of one variable to another, ie it increases or decreases within a certain range. The top tip here is to keep it superficial, don’t think in too much detail, the effect is either than A causes B to increase or decrease.

When answering these questions, it’s a good idea to justify your answers by including numerical values from the graphs. 

This will not only confirm your own confidence but also make it clear to the examiner you’ve interpreted the graph correctly. 

Compare and Contrast Questions

These questions are asking you to find similarities and differences between different data groups. 

The easiest way to make sure you’re staying focused to these questions is to split your answer into 2 sections: one for comparisons/similarities and one for differences/contrasts. 

This will make it clear to the examiner (and yourself) that you are giving appropriate answers.

Then, you should identify the exact variable you are asked to compare between two groups.

Eg. are you asked to compare the absolute glucose concentration between two variables or the decrease in glucose concentration (which is referring to a change and not absolute values). 

Also, make it super obvious when you are contrasting, by using phrases like ‘on the other hand’ or ‘whereas’.

This will again make it obvious to your tired examiner that you understand there is a difference between the two. 

Let’s take the following example:

Compare and contrast the concentration of blood glucose resulting from the embryonic stem cell transplant with the control

Answer:

Similarities:

Both groups show a gradual increase in blood glucose concentration after the initial decrease

Differences:

The initial decrease in glucose concentration is much greater in the transplant group than in the control group

The average blood glucose concentration is lower in the transplant group than in the control group for initial 2 weeks

Hopefully, you should realize the differences and similarities are really basic and a 5th grader could probably have recognized the trends, but the key is to be able to look for them very systematically. 

Evaluate/Discuss Questions

These questions are asking you to appreciate how a graph would support or refute a hypothesis or statement.

Typically the questions are phrased like this: Based on the graph/data above, evaluate if the conclusion XXX is supported.

It’s easy to get nervous when answering these, but you shouldn’t.

All you have to do is list the strongest factors that support or don’t support the conclusion and then synthesise a final evaluation at the end.

There are ALWAYS arguments for and against the conclusion.

Typically, the trend in the graph will need to be discussed.

Also, bear in mind that it is rare that the general trend is a perfect correlation, therefore a few data points will always go against what the overall trend is.

Consider the example below: 

Graph showing average CO2 concentrations over the past 50 years

Evaluate the conclusion that CO2 concentrations have been rising constantly for the past 50 years 

In this example, showing CO2 levels over the past 50 years, the general trend in the graph is obviously a strong positive correlation. However, when answering the question, it would also be relevant to mention that in every year, there has been a decrease in CO2 concentrations during some of the months.

The key skill that the IBO is testing here is the ability to not only list the data that supports or refutes a conclusion, but also for students to be able to decide which data is more relevant.

In the context of the graph above, it would therefore be appropriate to say that although there is a yearly decrease in CO2 during the first months, the average values for every year have been increasing and therefore the conclusion is supported. 

Here is a summary of the above information 

Types of DBQ Questions

1. State/Identify

   • Simple questions that ask you to identify a value from the graph (e.g., max/min values).

   • Tip: Always include units!

2. Calculate

   • Involves basic math—usually adding, subtracting, or calculating percentage difference.

   • Tip: Always use the original value as the denominator for percentage calculations.

3. Outline/Describe

   • Requires describing a trend or specific feature in the data.

   • Tip: Use specific numbers from the graph to support your description.

4. Compare and Contrast/Distinguish

   • Focus on identifying similarities and differences between data groups.

   • Tip: Organize answers with clear sections for similarities and differences, using phrases like “on the other hand.”

5. Evaluate

   • Examine whether the data supports or contradicts a hypothesis.

   • Tip: Provide both supporting and opposing points, then conclude with a balanced summary.

General Tips

• Think of the Examiner as a 5-Year-Old

  • Make each sentence address one key point for clarity.

• Match Your Points to Marks

  • If it’s a 3-mark question, aim for 3 distinct points.

• Lead with Strong Points

  • For complex questions (e.g., Evaluate), start with your strongest points to help the examiner find your answers quickly.

• Avoid Repetition

  • Each question often builds on the previous one. Don’t restate previous answers; try to bring new points.

Answering Different Types of Questions

• State Questions

  • Find and write down values directly from the graph, such as max or min values.

  • Example: “State the highest lipid content achieved by any group in the graph above.”

    • Answer: 198 mg/g, dry cell weight.

• Calculate Questions

  • Perform simple calculations, e.g., find the difference or percentage change.

  • Example:

    • Site 1 bird mass: 29.8; Site 2 bird mass: 28.3

    • Calculation: 29.8−28.329.8×100=5.3%\frac{29.8 - 28.3}{29.8} \times 100 = 5.3\%29.829.8−28.3​×100=5.3%

• Outline/Describe Questions

  • Describe data trends like positive/negative correlations or effects between variables.

  • Tip: Use data points to justify answers, showing you understand the data.

• Compare and Contrast Questions

  • Clearly separate similarities and differences in your response.

  • Example: “Compare and contrast the blood glucose levels in the transplant vs. control group.”

    • Similarity: Both groups show an increase in blood glucose after an initial dip.

    • Difference: The initial dip is greater in the transplant group.

• Evaluate/Discuss Questions

  • Assess how data supports or refutes a statement, considering both for and against.

  • Example: “Evaluate if CO₂ concentrations have risen consistently over 50 years.”

    • Answer: CO₂ has generally increased, but seasonal decreases occur each year. The trend supports the statement overall.