Structure: The report as argument

It is useful to see your whole report as an argument which relates back to your aim and supports how you carried out your experiment and the interpretation of your results. Notice how the information flows through the report from general to specific. Click on the Report button at the top of this screen to see an example of a whole report.

Ordering of informationReport structureDevelopment of argument
general
Title 
specific
Introduction
  • What do I intend to do?

  • Why is it important?
Study design
(optional)
specific
Results
  Legend  
general
How can I persuade my reader that my report has been worth reading?
Discussion
and Conclusion
  • What is the significance of my findings?

  • What are the limitations of my findings?

  • What claims can I make about my findings?

  • What recommendations can I make?

You need to remember your aim and make references to it when you are writing your results and discussion. In this way, you will link the results and discussion to the overall purpose of your report and remind your reader about why you are carrying out the experiment.

Click on the highlighted text in the aim to see how words and phrases in the aim are connected to other parts of the report.

Varying the Dietary Intake of Cholesterol May Cause Changes in Plasma Cholesterol Concentration in Middle Aged Subjects

This study aimed to determine if dietary intervention with low- or high-cholesterol diets could affect cholesterol levels in middle aged subjects.

Study Design

Figures 1 and 2. Effect of high- and low-cholesterol diets on blood cholesterol concentration.

Subjects (Table 1) consumed a high (n=3) or low (n=4) cholesterol diet for up to 3 months. Plasma obtained from samples obtained at the times shown were analysed for cholesterol by incubation in 100 mM Tris-HCl, pH 7.7 containing 1 mM aminoantipyrine (AAP), 6 mM phenol, 1 mM sodium cholate, 2.8 U/ml peroxidase, 7.4 mM Triton X-100, 0.65 U/ml cholesterol esterase and 0.45 U/ml cholesterol oxidase. After 10 min at room temperature, the absorbance of the incubation mixture was determined at 500 nm. The extinction coefficient of the red colour produced when AAP is oxidised by the hydrogen peroxide produced in the cholesterol oxidase reaction, was 1 mM-1 cm-1. *P<0.01 for difference between low- and high- groups.

Conclusions

Consumption of a high cholesterol diet did not significantly increase blood cholesterol concentration over a 12 week period (Figure 1) Similarly, over the same period, consumption of a low cholesterol diet did not significantly reduce plasma cholesterol concentration. However after 12 weeks the plasma cholesterol concentration of the high-cholesterol diet group was 50% greater than that of the low-cholesterol group (P<0.05). This result should be interpreted with caution because each of the 3 subjects used in the analysis for the high-cholesterol group finished the study with an identical plasma cholesterol concentration of 8 mM (probably coincidentally). When the results were expressed as a change relative to the subjects' starting cholesterol concentration (Figure 2), there did appear to be a difference between the two dietary regimes. Although this difference did not attain statistical significance (P=0.06) it is possible that a better designed study could have given more definitive results.

In this study, the sample size was small (n=3-4 for each group) and was heterogeneous with respect to age, weight, starting cholesterol concentration and other lifestyle factors. In addition, each subject only consumed either the high- or low-cholesterol diet and a cross-over study in which each subject consumed both diets for 12 weeks would have improved the validity of the data. The greatest problem with this study, however, was compliance. Some individuals indicated that they had not complied with the dietary advice and were omitted from the final analysis but it was impossible to determine how accurate the exact dietary intake of each subject or even whether they had consumed high- or low-cholesterol foods. Certainly the precise consumption of cholesterol was not monitored and could have varied from week to week.

In a future study, it is recommended that more subjects of both sexes be chosen; that meals of known cholesterol content are prepared for the subjects and that their compliance with the dietary regime be monitored effectively; and that each subject acts as their own control by consuming both diets in a randomised, cross-over sequence. Even then, any conclusions pertaining to the influence of dietary cholesterol on plasma cholesterol concentrations would be limited to Caucasian, middle-aged omnivores.

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