Thesis >> Discussion
The Discussion chapter in a thesis usually appears after, or may be combined with, the Results chapter. The Discussion consolidates and gives meaning to the results both in terms of answering the research questions and in the wider context of their contribution to the field of research. It is in this chapter that the writer makes claims about the significance and implications of the results.
Summary of key aspects of the Results and Discussion chapters
Results |
Discussion |
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Depending on the complexity of the research, the number of experiments or studies conducted, or the field, the Discussion can be combined with the Results and may not appear as a stand-alone Discussion.
Read the extract from the Discussion of a Computer Engineering Thesis about continuous collision detectio
Use the colour palette below to paint the sentences which address the following purposes.
- Approach followed to obtain the results.
- The writer’s claim about the significance (the importance of the findings and what they mean) of the results.
- Reference to experimental and numerical results.
- The key application of the results of the experiment.
- Recommendations for directions for future research.
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The purpose of the Discussion is to interpret the findings reported in the Results and explain what they mean and whether the objectives of the study have been achieved. Areas of discussion may include the usefulness, relevance, limitations and possible applications of the research. To demonstrate the advances made, the writer should position the results within the context of the existing literature and broader knowledge base. The writer may need to explain whether the results extend, agree with, or conflict with previous studies.
The Discussion includes the writer’s interpretation of the results and their opinion about the significance of their studies. Whereas the Results reports what was found in the study, the Discussion explains what these results mean. For this reason, a brief summary of the results may be included, but the writer should avoid too much repetition, as describing the results is not the purpose of the Discussion.
The Discussion may typically include the features below.
- A brief overview of the study with references to the objectives, key results and approach used in the study.
- Explanation, interpretation and evaluation of the results.
- Writer’s claim about the significance of the results and how they address the research gap.
- Comparison with previous work to support the discussion and to show how the results agree with, contradict or contribute to established knowledge.
- Limitations of the results or study with possible explanation to show how the limitations would affect the validity of the results.
- Suggestions for further research and practical applications of the research findings.
Activity 1
Read the sentences below taken from an Electronic Engineering thesis and decide which ones would fit the purpose of a Discussion section.
Show your answer by clicking on √ or X in each box.
Examples | √ or X | √ or X |
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| √ or X
This falls within the purpose of the Discussion as the writer is referring to future studies.
Check |
√ |
| √ or X
This falls within the purpose of the Discussion as the writer is referring to future studies.
Check |
√ |
| √ or X
This falls within the purpose of the Discussion as the writer is highlighting the significance and contribution of their work.
Check |
√ |
| √ or X
This falls within the purpose of the Discussion as the writer is highlighting the significance and contribution of their work.
Check |
√ |
| √ or X
This fits the purpose of the Results as the author is presenting the key results, followed by more details of the results.
Check |
X |
| √ or X
This does not fall within the purpose of the Discussion as the focus here is presenting the results.
Check |
X |
| √ or X
This falls within the purpose of the Discussion section as the writer is referring to future research.
Check |
√ |
Adapted from: D. Wang, “Deciphering Inter- and Intra-molecular Interactions Based on the Dynamic and Structural Properties of Molecules”, Ph.D dissertation, Dept. of Elec. Eng., CITYU, Hong Kong, 2014. [Online]. Available: CityU Institutional Repository. *GPU- Graphics processing unit, FGPA- field programmable gate array |
The structure of the Discussion will depend on the purpose of the study and whether it is combined with the Results. For theses involving multiple studies, there may be a Discussion chapter after each Results chapter, meaning that a thesis may have several Results and Discussion chapters. Some writers may choose to include an introductory section to preview the content of the Discussion and a concluding section which reiterates the main points.
In order to contextualise and integrate the Discussion with preceding chapters, the author may begin by referring to the key findings, the objectives or research gap of the study as outlined in the Introduction, and methods followed, so that the reader does not need to go back to these chapters. The remainder of the chapter is typically structured around the author’s discussion of the significance and implications of the results.
The Discussion is structured around the logical development of the writer’s evaluation and reasonable claims about the results. This is done by briefly referring to the results and then explaining what they mean in terms of their significance and implications. There may also be figures and tables illustrating key results that help to underpin the writer’s argument. Throughout this section, the logical flow of the writer’s argument is key, rather than the presentation of results, which is the purpose of the Results.
The Discussion may be presented as one stand-alone chapter and divided into subsections to reflect their content and areas of analysis. Examples of these include limitations, implications and applications.
Example 1
Below is an extract from the Table of Contents of a Systems Engineering and Engineering Management thesis which shows an example of a generic Discussion title with specific names, containing key words from the thesis title for the sub-sections to indicate the content.
Chapter 8 Discussion |
Generic title
Specific sub sections
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Adapted from: W. L. Ha, “Improving Embedded Software Development Performance through Modular Reuse” Ph.D dissertation, Dep. of Systems Eng. and Eng. Mgt., CITYU, 2013. [Online]. Available: CityU Institutional Repository. *ESR- Embedded software reuse |
Note: In Example 1, the discussion chapter is divided into four sections: the development of the ESR model, its application, implementation and limitations.
Moves in the Discussion
The Discussion may include the following three communicative moves or features and the steps that help to achieve them. Authors may not include all the steps depending on the nature of their studies.
Moves |
Steps |
Review of the present study |
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Discussion of results |
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Limitations and recommendations |
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Other possible moves include:
- Introductory statements to preview the content of the chapter
- Writer’s comment on anomalous or unexpected results
- Concluding statements to reiterate the main points and claims
If more than one set of results is discussed, the moves may be repeated.
Example 2
Below is an extract from the Discussion of a Systems Engineering and Engineering Management thesis with the key moves explained.
Click on the numbers in brackets to read an explanation of each part.
4.4 Discussion |
Adapted from: N. H. Tsang, “Multi-task performance in processing four-choice spatial stimulus-response (S-R) mappings: Implications for multimodal human-machine interface design”, Ph. D. dissertation, Dept. Syst. Eng. & Eng. Mgt., CITYU, Hong Kong, 2014. [Online]. Available: CityU Institutional Repository. *S-R- stimulus response, RMSTE- root mean square foot tracking errors, RT – reaction time, BC- both transverse and longitudinal compatible. Note: (…) indicates that parts of the text have been removed due to space constraints. |
Linking ideas to improve structure
Linking devices show the logical connection between ideas and help to improve the structure and logical flow of the text. Although they are an essential element of any piece of extended writing, they should not be overused as this can make the writing seem mechanical and unnatural.
As well as using linking devices, the author should use other techniques to help the flow of ideas, such as organising sentences so they begin with given information before moving to new, using the definite article “the” and pronouns to refer to what has been mentioned.
Below is a table containing some commonly used linking devices with examples taken from an Electrical Engineering thesis investigating the fabrication of novel optical fibers.
Table 1 | ||
Function |
Linking Devices |
Example |
Purpose |
in order to |
An ultrahigh birefringence PCF with an elliptical core was fabricated in order to evaluate its efficiency. |
Comparison and Contrast |
however |
High sensitivity and detectability make this a promising and potential device for microfluidics, regardless of connection with external microfluidics devices. |
Cause and effect |
because |
Because the length of the *FBG is very short, the temperature along the grating can be assumed to be uniform |
Emphasis |
in particular |
In fact, this device can effectively integrate the microfluidic flowmeter in one chip and measure the flow rate of the fluids in micro-channels. |
Adapted from: Z. Liu. “Fabrication of Novel Optical Fibres and Their Sensing Applications”, Ph.D dissertation, Elec. Eng., POLYU Hong Kong, 2015. [Online]. Available: PolyU Electronic Theses. *FBG- fibre Bragg grating |
Strategies for Improving Idea Flow
Below is a table containing alternative language strategies to improve the flow of ideas, with examples taken from an Architectural and Civil Engineering thesis.
Table 2 | |
Language Strategy |
Example |
Referring back to results obtained |
The results of the research interview show that the housing price models developed in Stage 2 of this research are merely an indication for the transaction data collected in 2006. |
This |
Triangulation was used in this research so as to deliver a more reliable result |
Repetition of key words to connect sentences |
It is true that the regression analysis conducted in this research is a case study in the relative steady period. However, Fellows and Liu (2008:110), point out that case study is suitable for in-depth investigation of an incident. |
Starting a sentence with old information or reference to subject of previous sentence |
It can be seen that the coefficients of the recalibrated models are different from that of the developed models. The difference can be explained by two reasons. |
Recalling previous sections to connect the overall chapter |
In the previous section, comparisons were made of the differences between the ‘Survey Results in Stage ‘1 and ‘Housing Price Model developed in Stage 2’. |
Previewing content |
The research findings demonstrate that the residential unit price models in Hong Kong and Macau have a high level of similarity. The above phenomenon is further discussed in this chapter. |
Adapted from: K. To “An Analysis of the Determinants of Housing Transaction Prices in Hong Kong and Macau”, Ph. D dissertation, Dept. of Civil and Arch. Eng., CITYU, 2014. [Online]. Available: CityU Institutional Repository. |
Example 2
Below is an extract from the Discussion chapter from an Electronic and Information Engineering thesis which shows an example of how different strategies for improving ideas flow are used.
Click on the numbers in brackets to read an explanation.
(1)To demonstrate the superiority of GOASVM over other state-of-the-art *GO methods, experiments were conducted on the EU16 dataset and the HUM12 dataset, respectively. Table 9.4 compares the performance of GOASVM against three state-of-the-art GO-based methods on the EU16 dataset and the HUM12 dataset, respectively. (…) |
Adapted from: S. Wan, “Protein Subcellular Localization: Gene Ontology Based Machine Learning Approaches”, Ph.D dissertation, Elec. and Inf. Eng., POLYU Hong Kong, 2014. [Online]. Available: PolyU Electronic Theses. *GO- Gene Ontology Note: (…) indicates that parts of the text have been removed due to space constraints. |
Activity 1>> 2>> 3
Below is an extract from the Discussion of a Mechanical and Biomedical Engineering thesis.
Read each part and select the best label. Click on check to see the answer.
Extract | Moves | Correct Answer |
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In this work, we developed a computational model to transfer the genotypic data to phenotypic data for specialized subjects, by characterizing the *EGFR-inhibitor interaction patterns and taking personal features into consideration. (…) | Reference to results with author’s evaluation of what they mean Directions for future research Reference to the objective and the methodological approach of the study Significance of the results “In this work” and the verbs “we developed” and “to transfer” express the objective of the study. The approach used in this study is indicated in the expression “by characterizing the EGFR-inhibitor interaction patterns and taking personal features into consideration”
Check | Reference to the objective and the methodological approach of the study Note: “In this work” and the verbs “we developed” and “to transfer” express the objective of the study. The approach used in this study is indicated in the expression “by characterizing the EGFR-inhibitor interaction patterns and taking personal features into consideration” |
*ELMs were adopted in this work, and the combination of ELMs and leave-one-out cross-validation produced a successful identification of resistant subjects with high accuracy. (…) Results are shown in Table 2.11, where the prediction accuracies underperform those produced by ELMs, indicating the effectiveness of ELMs in this prediction work. | Reference to results with author’s evaluation of what they mean Directions for future research Reference to the objective and the methodological approach of the study Significance of the results The author refers to a key result of the study which is the “high accuracy” of the identification of resistant subjects and supports this by referring to a table showing the results. Evaluative language “indicating the effectiveness of…” expresses the author’s evaluation of what the results mean.
Check | Reference to results with writer’s evaluation of what they mean Note: The author refers to a key result of the study which is the “high accuracy” of the identification of resistant subjects and supports this by referring to a table showing the results. Evaluative language “indicating the effectiveness of…” expresses the author’s evaluation of what the results mean. |
Our method can be regarded as a personalized prediction model for drug resistance, based on both the mutation feature and the personal features of a patient. With a high prediction rate for drug resistance, our model encourages the development of personalized medicine/therapy design. | Reference to results with author’s evaluation of what they mean Directions for future research Reference to the objective and the methodological approach of the study Significance of the results “Our method can be regarded as …” indicates the author is commenting on the contribution of the model to highlight the significance of this part of study.
Check | Significance of the results Note: “Our method can be regarded as …” indicates the author is commenting on the contribution of the model to highlight the significance of this part of study. |
Future research will include exploring more accurate and powerful approaches to predict the 3D structure of a specific mutation, based on its sequential information. This will improve the prediction model and help us update the library based on the new data. Future studies will bring more benefits to the investigation of mutation-induced drug resistance and innovative drug design. | Reference to results with author’s evaluation of what they mean Directions for future research Reference to the objective and the methodological approach of the study Significance of the results “Future research will include…” indicates directions of the research with the potential benefits to the wider community indicated by “this will help to advance…”
Check | Directions for future research Note: “Future research will include…” indicates directions of the research with the potential benefits to the wider community indicated by “this will help to advance…” |
Adapted from: D. Wang, “Deciphering Inter- and Intra-molecular Interactions Based on the Dynamic and Structural Properties of Molecules”, Ph.D dissertation, Dept. of Elec. Eng., CITYU, Hong Kong, 2014. [Online]. Available: CityU Institutional Repository. *EGFR – Epidermal Growth Factor Receptor, ELM – Extreme Learning Machine Note: (…) indicates that parts of the text have been removed. |
Read the extract from a combined Results and Discussion of a Civil Engineering thesis and highlight the sentences that match the labels. Note that they may appear more than once if more than one set of results is reported.
Click on the palette below to colour your choices.
- Reference to a table which illustrates the results and highlighting results presented in it
- Examples of results to support the discussion
- Significance of the results
- Comparison with previous studies
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Below is an extract of the Discussion from an Architectural and Civil Engineering Management Thesis about fibre-reinforced polymers in concrete columns.
Some phrases have been removed. Read through the text and fill the gaps by dragging and dropping the phrases from the table into the correct spaces.
this identical value interestingly but in order to evaluate those furthermore |
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Click on the numbers in the text to read an explanation
(1) In order to evaluate the non-homogeneity coefficient of FRP jackets, two sets of data from the test results in Chapter 3 and (2) those from Teng’s group (Lam and Teng 2004; Lam et al. 2006) were analyzed. The average values of εave and εmax for different FRP thicknesses are calculated and compared in Fig. 4.5. (3) Interestingly, the gaps between the two curves for εave and εmax are constant for both sets of data when the thickness of FRP jackets changes. (4) This identical value demonstrates that the strain variation along the perimeter is less affected by the workmanship of jacketing and FRP properties (which could be different for the two series), (5) but largely results from the non-homogeneity of concrete (which was similar for the two series). (6) Furthermore Table 4.4 shows that the value of SD or cv for both series is small, which confirms the general belief that the ultimate confinement for circular columns is approximately uniform along the perimeter. |
Adapted from: J. Jiang, “Plasticity Modeling and Experimental Study of Fibre-Reinforced Polymer (FRP)-Confined Concrete Columns”. Ph. D dissertation, Dept. of Arch. And Civil, Eng., CITYU, 2012. [Online]. Available: CityU Institutional Repository. * FRP- Fibre-Reinforced Polymer, εave – average value of lateral strain in non-overlap zone, εmax – maximum strain in FRP jacket, SD- standard deviation, cv– cumulative variance, μ/SD |
Whereas the focus of the Results is to report the facts of the study (the results), the Discussion focuses on the writer’s evaluation of their significance (why they are important) and implications (how they affect the wider community and can be applied). Therefore, the writer needs to use evaluative language that expresses the correct degree of certainty because the writer needs to avoid making false claims which could discredit the value of the work. In this case, using cautious language is key and helps to separate facts from opinion in this section.
The Discussion features a mix of Present Simple tense to express the writer’s opinion about the results and Past Simple to report what was done and achieved or observed. Future tense may also appear to express future applications or research possibilities.
Common language features of the Discussion include the following items.
- Evaluative phrases to discuss the significance and implications of the results
- Comparative and contrastive phrases to discuss results in relation to previous work
- Cautious language to explain and suggest contribution or limitation of results
- Present Simple tense to evaluate results and express the writer’s opinion
Example 1
Below is an extract from the Discussion of a Mechanical and Biomedical Engineering thesis. Examples of the common language features of this chapter have been highlighted.
- Past Simple is used to describe the objective of the study.
- Present Simple is used as the author is evaluating considerations in the study and referring to results shown in a figure.
- Comparative and superlative language to highlight the strength of the choices made
- Evaluative language to express author’s opinion
- Linking devices to improve idea flow
- Cautious language to avoid overstating claims
Click on the numbers in square brackets in the text to read an explanation of the language feature used.
The objective of this study was to develop new gigapascal strength ferritic steels (NCPS) through tailoring co-precipitation of nano-carbides. From a technological standpoint, both weldability and material cost are important considerations when selecting gigapascal strength steel materials for structural applications. Figure 4.15 shows the weldability and cost effectiveness of the NCPS steels in comparison with available literature reported 1.5 Gpa strength steels. Maraging steels have the highest weldability but are prohibitively expensive, whereas medium carbon martensitic steels have the highest cost effectiveness but suffer from poor weldability. The currently developed NCPS steels occupy a unique spot with an outstanding combination of good weldability and high cost effectiveness, and thus are promising for future structural applications. In addition, the NCPS steels shed new light on the metallurgical design of gigapascal strength steels. Figure 4.16 shows the C and Ni contents in the NCPS steels and other conventional 1.5 GPa strength steels. Experimental data so far indicates that the 1.5 GPa strength is typically obtained in steels with either high Ni or high C. By contrast, the NCPS ferritic steels with only 3-7 wt.% Ni and 0.03-0.07 wt.% C additions exhibit the comparable mechanical properties, demonstrating its unique combination of superior properties including high strength, good weldability, and low material cost. More importantly, the development of the NCPS steels creates a new compositional domain for the 1.5 GPa strength steels and opens a new way for strengthening ferritic steels. This study, is just a demonstration for the computational-aided alloy design of advanced gigapascal strength steels. This alloy design approach, in principle, can be applied to explore new steels by incorporating nanoscale precipitation strengthening, which provides a very effective route for tailoring the precipitation configuration by optimizing the alloy composition and processing parameters. |
Adapted from: Z. Jiao, “Alloy Design, Characterization, and Mechanical Properties of Advanced Ultra-high Strength Steels Strengthened by Nano-precipitates”. Ph. D dissertation, Dept. of Mech. And Bio., Eng., CITYU, 2014. [Online]. Available: CityU Institutional Repository. |
Evaluative Language
As a key feature of the Discussion is to account for and make claims about the significance of the results, it is important that the author uses the appropriate amount of caution when evaluating the findings of an experiment. This is achieved by a combination of using modal verbs (may, might, could), adverbs (possibly, significantly) and evaluative verbs (indicates, suggests) which present the author’s opinion about the results.
Below is a table containing some phrases used for evaluating results and using cautious language, taken from a Mechanical Engineering thesis about LPG flames, to show how they are used in context.
Purpose |
Phrase |
Example |
Confidently stating the significance and implications of the results |
The results confirm… |
The results clearly show that O2 enhancement can significantly expand the reaction zone of LPG IDF. |
Cautiously making comments about the significance and implications of the results |
This result indicates that … |
This result indicates thatLPG IDF can be stable under a very fuel-lean condition, that in the early stage of combustion, hydrogen |
Accounting for unexpected or anomalous results |
The … might be attributed to … |
The difference in results might be attributed to the difference in burner geometries and fuel properties. |
Cautious explanation of results
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The effect of … may be due to… |
The reason for the flame to be stable with a smaller energy supply rate after adding H2 may be due to an improved air/fuel mixing caused by the high burning velocity and diffusivity of hydrogen. |
Comparing results with previous research |
Several researchers also found that … |
Several researchers also found that H2 can effectively reduce the fuel-lean blowout limits of flames (Burguburu et al., 2011; Frenillot et al., 2009; Karbasi, 1998; Schefer, 2003). |
Drawing conclusions from data |
It may be concluded that … |
It may be concluded from the data and experimental phenomenon that LPG IDF is able to maintain the form of incomplete flame for a narrow range of fuel flow velocity, and a complete extinction usually occurs almost immediately when fuel flow velocity reaches the critical level. |
Adapted from: J. Miao, “Combustion, Thermal and Emission Characteristics of Gas-fired Inverse Diffusion Flames Burning Mixed LPG- Hydrogen Fuel”, Ph.D dissertation, Dept. of Mech. Eng, POLYU. [Online]. Available: PolyU Electronic Theses. |
Activity 1>> 2
Below is an extract from the Discussion of a Computer Science thesis.
The phrases which show the appropriate degree of certainty have been removed. Complete the text by clicking on the correct phrase from the multiple choice options.
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Click on the numbers to see an explanation of each answer.
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Below is an extract from the Discussion of an Architecture and Civil Engineering thesis discussing the limitations of the analysis.
The main verbs have been removed. Complete the text by selecting the correct tense for each verb, by clicking on the options below the text for each gap.
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Click on the numbers to see an explanation of each answer.
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