Writing Guide Home Conclusion & Evaluation  


This should be a clear and precise statement where you give a valid conclusion after looking at your data.

It should still be precise; you shouldn’t give a general statement like: “The rate of reaction increase with temperature but then decreases”. You should say something like: “The rate of reaction of the enzyme increases up to 40˚C but as the temperature continues to increase, the rate of reaction decreases.”

There can be more than one conclusion.

Explanation of the Conclusion

This is the part where you support the statement you made in the conclusion.

You must:

● Refer to data (use specific examples)
● Refer to graphs (use specific examples)
● Refer to your hypothesis (If you designed the experiment)
● Refer to your explanation of the hypothesis (If you designed the experiment)
● Refer to literature values or principles that you can get from (don’t forget to reference):

◦ Textbooks
◦ Syllabus
◦ Websites

Results Evaluation

Evaluation means you are expected to say how it impacts on your results either in a positive or negative way; this is where you apply a critical eye to your data and graphical representation of the data.

You need to take the following points into account but remember to explain them:

● Is your data reliable? Discuss any anomalous data and reliability even if there is no anomalous data.
● What are the unexpected results (if any)?
● Are the uncertainties significant? 0.5 g ± 0.1 g is a very large uncertainty and likely to be significant.
● If you done a statistical test, does it show consistency between results or does it prove a significant difference between the sets of data?
● If applicable talk about how far the calculated value from your statistical test is from the critical value. The further away the calculated value is from the critical value, the more convincing your result is. Remember that some tests are known as being more powerful than others so conclusions drawn from a t-test are more convincing than from a Mann Whitney U test. Also, if you have fewer samples in your sets of data than the suggested amount for the test, this will reduce the validity of the analysis.
● How strong is the proof provided by your graph? If it shows a correlation, how strong is it? If it shows a trend, how obvious is it?

Procedure Evaluation

Before you start trying to find weaknesses in the procedure, bear the following points in mind:

● I will always give you procedure with weaknesses in them so you have something to write about
● If you are carrying out an experiment you designed, there are bound to be some weaknesses in the procedure however good you are.
● When you do an experiment, always make a note of something that goes wrong as it may help you in this stage

You should try to identify at least three weaknesses, more if possible.

Weaknesses do not include your mistakes! If you misread the ruler or didn’t bother to measure the volume accurately that is more proof of incompetence than procedural problems so don’t mention anything like this.

Weaknesses include but are not limited to:

● Range of data
● Inappropriate equipment for the task: measuring 1 cm3 using a 100 cm3 measuring cylinder
● Equipment required not in the apparatus list
● Equipment was faulty: a faulty air pump when using a pipette is a common one
● Reliability: having enough data
● Accuracy: getting accurate readings from the equipment used

You should say how these weaknesses would have affected your data and if applicable how they could have resulted in your anomalous data.

Suggested Improvements

For every weakness you identify, you must suggest an improvement and you must be very specific. Generic comments like "increase concentration" or "increase the number of repeats" without quantifying it are meaningless and comments like "use more specific equipment" without specifying what equipment are also meaningless.

Suggestions have to be realistic. You have to be able to carry out the suggested improvements so no point telling me to use the Large Hadron Collider at the CERN, to use radioactive markers in DNA analysis or an electron microscope. I don’t have access to any of those things!

You should explain why the suggested improvement would make the procedure better. For example, a digital clock would give a more precise reading than an analogue clock as it has an uncertainty of 0.01 seconds rather than 1 second.

If you thought the procedure was wrong (it can happen), suggest how the procedure itself could be changed to ensure more reliable results (or any results at all if it didn’t work and you got no data).

Include how you could change it to get more valid results. This could be done by changing concentrations of solutions or if a better variable could be measured, suggest a different one.

Suggest further investigations that are possible.