Module 7: Results and Discussion Sections of Scientific Papers

Module 7: Results and Discussion Sections of Scientific Papers

Compiler: Dr Hester Oosthuizen

1. Introduction  

The general format for scientific research articles is the IMRAD format, which consists of the following sections: Introduction, Methods, Results, and Discussion. Although this format is a logical order, it is not suitable for all subjects and topics. Furthermore, journals might prefer a different order or combination of sections. Typically, the Results and Discussion sections are two different sections but often it makes sense to combine the two. In addition, some journals require a separate Conclusion section, while other journals intend for concluding remarks to be stated at the end of the Discussion section. Combined or separate, whatever the case might be, the results of a study in any article needs to be firstly reported and then discussed followed by an overall conclusion. However, it is important that the readers are able to clearly distinguish between the results and the discussion of the results.

The results are the findings, but not the raw data, of your research and can be seen as neutral information. In other words, if your research is repeated by other scientists, they should get the same results.

On the other hand, when you are discussing the results, you are interpreting them, using logical reasoning to formulate conclusions based on the results. Other scientists might differ on your interpretation of the results. Therefore, if the two sections are combined, it is important to distinguish between what you found (results) and what you think it means (discussion and conclusion).

This distinction is illustrated in the following example taken from Plasma Chem Plasma Process, 31:427–439 (2011).

Example

We analysed two sets of mixtures. In the first set we kept the ratio R at a value of approximately one and changed the helium mole fraction. In the second set we kept the helium mole fraction constant at 85% and changed R. In all the mixtures studied the main products detected were H2, CO, C2H6 and C3H8 although we also found traces of liquid products and solid carbon deposits.

Breakdown Voltage

The first observable effect of the composition of the gas mixture was a change in the breakdown voltage, extracted from an analysis of the Lissajous figures obtained from the applied voltage, U, and discharge current, I. The dispersion in breakdown values for a given composition obtained by this method was large but we observed a clear reduction in breakdown voltage with increasing helium mole fraction as shown in Fig. 2. On the other hand, the R ratio does not seem to have any influence.

The results can be explained [34, 35] by the condition for self-sustainment in inhomogeneous fields, assuming that each discharge starts as a Townsend avalanche and using the Townsend coefficient values obtained for the electron kinetics in those mixtures.

Another feature in this example is the overall description of the experiment in the first two paragraphs. The detailed description of how the research was done appears in the Method or Experimental section. It does, however, help your reader if you provide the “big picture” at the beginning of the Results section. Compare the amount of detail in the Experimental section to the lack of detail in the Results and Discussion section. This illustrates the difference between the “big picture” of the Results and Discussion section and the detailed picture in the Experimental section.

Experimental section of the same article

The experiments were performed in a cylindrical DBD reactor (Fig. 1) having a central Stainless Steel electrode of 5 mm diameter, supported by MACORr fittings, inside a 10 mm I.D., 1 mm thick glass tube. The external (ground) electrode is an aluminium thin foil stretched around the glass. The chamber has a porous glass on one end, at a few millimeters from the tip of the internal electrode, used to support a catalyst. However, as mentioned before, the present results were obtained without a catalyst. At the exit of the chamber a trap cooled at 0 °C collects the liquid products. The sinusoidal power supply allows a maximum rms voltage of 10 kV. The measurements were obtained within a (4 to 6) kHz frequency range.

In this reactor we faced the problem of the formation of an arc during the experiments, which could damage the reactor. To avoid this, we performed several measurements with the outer wall of the reactor cooled.

Mixtures of He/CH4/CO2, where the helium mole fraction varied between 50 and 95%, were studied. The ratio R was changed from 0.2 to 4.2. The gas flows were controlled with standard mass flow controllers. The total gas flow rate was changed from (2 to 6) L/h.

2. Presentation of the results  

The results are the evidence that your research is contributing new knowledge to your field. Results, carefully presented, contribute greatly to the impression of research well done. Furthermore, the reader expects the logical presentation of the results, not the raw data or the chronological order in which the experiments were done. Not all data collected can be displayed, therefore include sufficient, relevant data to justify the conclusion. This, however, does not mean that data not supporting the hypothesis might be ignored.

Summarise the data in an acceptable format, either as a sentence in the text, or in a table, or in a figure. Very seldom the same data is presented using more than one form. In an article by Ashraf et al. (J. Chem Ed., 88(1): 44-48 (2011)), an exception to the rule, Figure 1 is a graph of the responses of the students to some of the questions given in Table 2. This example clearly illustrates that it is easier to see the trends in a graph than in a table.

Table 1: Results of the Student Survey (20 Respondents)a Strongly agree	Strongly disagree
Statement	5	4	3	2	1
1	I found this course very useful	65	10	20	5	0
2	The course taught me new and valuable skills	75	10	10	5	0
3	I already knew most of the content presented	25	20	25	20	10
4	I would recommend this course to my friends	65	25	15	0	0
5	I think this course will help me with my other classes	60	35	0	0	0

a Data expressed in percentage (%)

 

In choosing the best form for presenting the data, strive for clarity. Therefore find the form that communicates the message of the results effectively to the audience.

The following criteria can be used as a general guideline to decide on the best form:

· If the results can be summarised in one sentence, use the text. 

For example:

• Ø On the other hand, the R ratio does not seem to have any influence.

(Plasma Chem Plasma Process, 31:427–439 (2011))

• Ø The Grignard step resulted in yields ranging from 2.6 to 55.9%, with the average yield being 21.1%.  

(J. Chem.. Ed., 88(1):82-85 (2011))

· Tables are generally used when the exact values are important, or when there are no clear patterns, or if the results consist of a lot of words. Tables are two-dimensional, that is, they can be read from left to right and top to bottom. It is easier to compare data in a column than in a row. Repetitive data should not be given in a column, but should rather be included as a footnote. 

· Figures are generally used when you want to communicate trends and relationships, or when you want your reader to see the basic point at a glance. In scientific literature, the term figure is used for graphs, schemes, spectra, diagrams, photographs, flow charts, and so on. 

Each table and figure must have a caption consisting of its own unique number and title. The title is a concise description of the significance of the table or figure. If it is a graph, do not give the description on the axes as the title. The reader should grasp the meaning of the table or figure from the caption and should not need to consult the text.

Every table and figure must be referred to in the text by name and number. If you cannot find the place to refer to the table or figure, then it is an indication that you do not need the table or figure. Including references to tables and columns as part of the argument gives a more readable text than just referring to it. Compare the first example to the following two.

· Figure 1 shows the predicted equilibrium products for the reaction between A and B.

· The dispersion in breakdown values for a given composition obtained by this method was large but we observed a clear reduction in breakdown voltage with increasing helium mole fraction as shown in Fig. 2.  

(Plasma Chem. Plasma Process, 31:427–439 (2011))

· SEM investigations of the joint (Fig. 13) exhibited very good filler adhesion to the joined areas of the Al2O3 ceramic partners.  

(J. Nucl. Mater. 405:1-8 (2010))  

The first example is not incorrect, however it is fairly non-descriptive. The readers have no indication of what the important aspects of Figure 1 are. The authors of the other two examples draw our attention to the patterns that need to be noticed, while they still explicitly refer to the specific figure or table. They also did not simply repeat the citation or the data from the figure or the table in the text.

Find the conventions used in your subject regarding tables and figures (e.g. style manuals like The ACS Style Guide). Examples of such conventions include: figures should not have borders, words in columns in tables should be aligned left while numbers should be aligned at the decimal point, tables should not have grids but only three horizontal lines.

The Results section can be concise, provided the results are clearly stated.

Activity

Analyse the Results sections of a few publications in your field with regard to the following aspects:

· Are there any sentences in the Results section that could have been left out without changing your understanding of the results?

· How have the authors referred to figures and tables? Have they used a direct reference (Figure 1 shows …) or does the reference form part of the argument?

· List the types of graphics (e.g. graphs, photographs, etc.) and the kinds of data in each of the types.

· What claim in the text does each table and figure support? Does the chosen visual medium aid in understanding the claim? (You can test it by drawing, for example, a graph using the information in the table. Is it easier to get the message from the graph or the table? Has some important information been lost in the graph?)

· Is the table designed according to the conventions described in the style manual of your subject?

· Is it easy to distinguish between the results and the discussion? 

Examples of journal requirements

· Results should be clear and concise.

· In the Results section, include the rationale or design of the experiments as well as the results; reserve extensive interpretations of the results for the Discussion section. Present the results as concisely as possible in one of the following: text, table(s), or figure(s). Data in tables (e.g., cpm of radioactivity) should not contain more significant figures than the precision of the measurement allows. Illustrations (particularly photomicrographs and electron micrographs) should be limited to those that are absolutely necessary to show the experimental findings. Number figures and tables in the order in which they are cited in the text, and be sure to cite all figures and tables. 

New trends

The printing cost of publications is high and therefore the trend is to provide less detail in the publication with additional information available electronically as supplements. However, enough results need to be included in the text for the reader to follow the argument and understand the conclusions without consulting the supplement.

Tips

· Start the Results and Discussion section by giving the “big picture” of how the research was done.

· Give the results in a logical order, not a chronological order.

· State the results either in the text, a table, or a graph.

· Number tables and graphs in the order in which they appear in the text.

· All figures and tables must be referred to in the text, preferably as part of the argument.

· Tables and figures must be positioned in the body of the text after they have first been referred to in the text.

· Consult the author artwork instructions of the journal for requirements regarding figure preparation. 

3. The discussion of the results  

Why would scientists read your paper? In most instances it is because the findings of your study are related to their own research and they want to see how your research solved the problem or how the results of your study is adding new information or perspectives to their current knowledge. Even though the results are of the utmost importance, all by itself, it would not give the reader the necessary insight. The readers need to be told how the results were used to arrive at the conclusions given, thereby answering the research problem.

What are the elements of a good Discussion?  

· An interpretation of the results in terms of trends, characteristics, and so forth. For example: 

We observed a clear reduction in breakdown voltage with increasing helium mole fraction.

· Compare or explain your new results with reference to published data or theories. 

The results can be explained [34, 35] by the condition for self-sustainment in inhomogeneous fields.

· Point out any discrepancies and suggest possible explanations for these observed discrepancies. 

The only gas detected containing oxygen atoms, CO, does not account for all the oxygen atoms converted in the reactor. As the mole fraction of helium increases, the fraction of carbon and hydrogen atoms converted that are not detected in the gas phase also increases. The formation of condensable products that are retained in the trap or deposited in the reactor can account for this missing fraction.

· Discuss the implications of your work, both theoretical and practical. 

Although the admixture of helium reduces the energy consumption per mole, these values are still high for commercial application. Moreover, the separation of helium from the products adds another step to the process. The combination with a catalyst and/or a pulsed power supply is necessary to improve the efficiency of the process.

· Relate your results to the original purpose or aim of the research. 

(Examples taken from Plasma Chem Plasma Process, 31:427–439 (2011))

End the paper with a conclusion, either as a separate section or as the last paragraph of the Results and Discussion section (depending on the journal requirements if any). The purpose of the Conclusion is to:

· summarise the main findings;

· explain how the research question has been answered or partially answered;

· point out the advantages, disadvantages, and limitations of the current research; and

· mention which aspects of the research problem have still not been answered. 

Activity

Analyse the Discussion and Conclusion sections of a few articles in your field by answering the following questions:  

· Has the aim of the research, as given in the Introduction, been reached?

· What evidence was provided to substantiate that the aim was reached?

· Identify a few logical connectors in the Results and Discussion, and Conclusion sections, and explain their role in the text. 

Logical connectors are words or phrases used to indicate relationships in a scientific argument, for example it is used to state the contrasting side of the argument (e.g. but, despite), or qualify the initial statement (e.g. unless, although), or add information to what has already been said (e.g. also, further).

· Scientists use tentative or hedging verbs like suggest, possibly, indicate, rather than more strongly worded claims like prove, definitely, conclude, and so forth. Can you find any examples? 

To provide you with a better indication of how to go about the activity, let us work through an example (J. Chem. Ed. 88(1):82-85) (2011)). To be able to understand and analyse the Discussion section, it needs to be read in conjunction with the Introduction. For this purpose only a few relevant sentences in the Introduction have been presented from the example article. Read these sentences and the Results and Discussion section as well as the Conclusion section.

Introduction

One of the most widely studied reactions in an undergraduate course in organic chemistry is the Grignard reaction. Students learn the scope of the reaction and the types of functional groups that will undergo nucleophilic addition by the Grignard reagent, the limitations of the reaction, as well as the preparation of the Grignard reagent itself. .……

We have performed the sequence of experiments as described by Harwood and Moody for the 12 years and, even with some modifications in the quench step, our students have not achieved the results of the Grignard step as reported in the literature. …………

We set out to develop a synthetic procedure that would include the overall process of the original Paulson synthesis—protection, Grignard reaction, and hydrolysis—but would improve yields of products, minimize side reactions, and provide a distinct difference between quench and hydrolysis. It is our hope that our students will see that protecting groups and Grignard reactions do work well and can provide high yields of the desired product. We also want to make the distinction between quench and hydrolysis in a hands-on manner to reinforce the difference between the two methods in the lecture portion of the course.

Results and Discussion

We have now completed a round of this new procedure using ethyl levulinate in place of ethyl acetoacetate (acetal formation, Grignard reagent preparation and reaction, and deprotection-dehydration) with our second-term organic chemistry students and overall the process worked well. The students did this synthesis in pairs to minimize the materials and equipment needed, instrument time, and allow them to foster discussion of the procedures and results. Although there was one pair of students who did not have successful Grignard reagent formation and subsequently did not form the desired products and three other groups who did not properly record their data, the overall process was successful and without incident for the remaining 14 groups. The Grignard step resulted in yields ranging from 2.6% to 55.9%, with the average yield being 21.1%. As can be seen by comparison with Table 1, our results improved during the Grignard step, though student errors still occurred during the quench workup stage, and there was still some significant oil by-product during the crystallization stage of the Grignard product, thus, lowering some yields (these yields reflect isolated crystals after washing with ethanol). Overall, the process worked well and gave clear, decipherable spectral data (by IR, 1H NMR, and 13C NMR).

A more complete analysis of student results for each step in the synthesis can be found in the supporting information.

Conclusion

This synthesis of 5,5-diphenyl-4-penten-2-one, based on Paulson’s original three-step synthesis (protection, Grignard reaction, and hydrolysis-dehydration) and modified by Rivett and Baar et al., has great benefits to our organic laboratory students. In addition to showcasing two well-studied reactions in organic chemistry, namely, the Grignard reaction and the use of acetal protecting groups, this synthesis also emphasizes the difference between an acid/water “quench” and an acid/water “hydrolysis”. These are methods widely used in organic chemistry, yet the nuances utilized in each are lost to beginning organic chemistry students. By using these two methods in the laboratory, students better understand the difference when they see these reactions in the lecture portion of the course (as quench and hydrolysis are fairly common in organic chemistry reactions). Additionally, this reaction sequence teaches students how to deal with reversibility in reactions by shifting the equilibrium to the products using Le Châtelier’s principle (by removing a product, namely, by using a Dean-Stark apparatus to remove water), re-emphasizes the importance of spectroscopic methods in the lab (i.e., IR and NMR techniques), and highlights the challenges faced in a multistep synthesis project. Finally, we have vastly improved the yield in the Grignard step of this reaction sequence and have bypassed the further reaction of the Grignard product. This gives students better confidence in their lab abilities and reinforces their impression of the Grignard reaction. We are able to accomplish this three-step sequence in three lab periods, thus, not having to devote nearly an entire lab course to a larger synthesis project.

Now let us answer the questions originally posed.

· Has the aim of the research, as given in the Introduction, been reached? 

Answer

The aim was given in the last paragraph of the Introduction and in the Discussion and the Conclusion the authors described how they have reached the aim. The interaction between the Introduction, Discussion, and Conclusion is summarised as follows: Introduction	We set out to- develop a synthetic procedure that would include the overall process of the original Paulson synthesis—protection, Grignard reaction, and hydrolysis,
Discussion	We have now completed a round of this new procedure using ethyl levulinate in place of ethyl acetoacetate (acetal formation, Grignard reagent preparation and reaction, and deprotection-dehydration) with our second-term organic chemistry students …
Conclusion	This synthesis of 5,5-diphenyl-4-penten-2-one, based on Paulson’s original three-step synthesis (protection, Grignard reaction, and hydrolysis-dehydration) and modified by Rivett and Baar et al., has great benefits to our organic laboratory students.
Introduction	– would improve yields of products, but
Discussion	The Grignard step resulted in yields ranging from 2.6% to 55.9%, with the average yield being 21.1%. As can be seen by comparison to Table