Background material for Year 1 Semester 1 Med PPSD session on 12th November 2008
The goal of scientific writing is clarity. The following must be observed about sentences: short concise sentences, use of personal pronouns, subject-verb agreement is a common mistake, using active and avoiding passive sentences, proper organization of parallel ideas, and proper use of parentheses.
A paragraph must start with a short and simple topic sentence that is an overview of the message contained in that paragraph. Each paragraph should convey only one message. The sentences following the topic sentence provide details and support for the topic sentence. Ideas in a paragraph should be presented in the right order with no missing steps using one of the following alternatives: least to most important, most to least important, concise to the detailed, time chronological order, problem followed by solution, or solution followed by the problem. Links and transitions such as ‘which is’ should be used when moving from one group of ideas to another to ensure continuity in the paragraph. There must be consistency in the order in which information is mentioned. If certain objects were mentioned in a certain order in the introduction, they must be mentioned in the same order all through the writing. The writer should maintain a consistent viewpoint all through the paper and not appear to be jumping from point to point. Important messages must be given emphasis.
The purpose of the title is to identify the main topic or message of the paper so as to attract readers. A good title is unambiguous, concise, and contains important words. It should contain the following: independent variable(s), dependent variable(s), the study subjects or materials, and statement of the main message like ‘to study the effect of’, ‘to determine’ etc.
The abstract is an overview of the report with a few significant details. It should be written to be read by both those who read the full paper and those who do not read the full paper. Normally the abstract should not exceed 250 words. The abstract should mirror the sections of the paper: introduction, materials & methods, results, and discussion. The present tense is used to state the research hypothesis and the answer. The past tense is used for the experiment. An abstract is accompanied by keywords that are used for indexing.
The introduction should be short. It should start with stating the research question or research hypothesis and then go on to elaborate. The transition should be from the known to the unknown and from the big picture to the detail. The introduction should mention the type of study, the study subjects or materials (substances, animals, and persons). In some cases the introduction may briefly mention the proposed experimental approach to answering the research question. Results should not be mentioned in the introduction. The introduction should state whether the work is new or original.
The aim of the materials and methods section is to describe the experimental techniques in detail sufficient for another trained scientist to replicate the procedures. The order of presentation is different for animal and clinical studies. For animal studies the order is: materials and animals, preparation, study design, interventions, methods of measurement, calculations, and data analysis. For clinical studies the order is: study subjects, inclusion criteria, exclusion criteria, study design, interventions, method of measurement, calculations, and data analysis. Independent and dependent variables should be identified. Intermediate results can be put in the materials and methods section. Final results should be put only in the results section. Details of sample size determination should be provided.
The results section presents the findings of the procedures carried out in the methods section. It should be brief and to the point. A distinction must be made between results and data. Result refers to summary information obtained from data analysis. Results of hypothesis-based studies should be in the past tense. Data of descriptive studies should be in the present tense. Data is the actual numerical information often presented in a summarized form. The result is presented followed by presentation of supporting data. Data are presented in the form of tables and diagrams (figures, bar diagrams, graphs, pie-charts, maps etc). Presentation of numerical data in text should be kept to a minimum. Only results relevant to the research hypothesis should be presented. Both negative and positive results are presented. It is considered scientific fraud to present only those results that the author thinks favor a particular hypothesis. The results section is written in chronological order. The most important results are presented before the least important. Magnitude of change should be presented as a summary statistic such as percentage change instead of presenting the raw data. Summary statistics normally used as the mean, the median, and the the proportion. The mean should be presented properly as mean +/- standard deviation or standard error of the mean (SD or SE) with units of measure indicated. Measures of effect are normally the chisquare and the t statistics. Actual p values should be given instead of indicating <0.05 or >0.05. When specifying the sample size the type of sample should be explained for example ‘the sample was 20 rats’ instead of the sample size was 20’. Emphasis can be put on some results and not others. Not all the data from the study need be reported. Citing data in the text takes less space but is more difficult to read. A topic sentence is used to give an overview. Important results are put first.
Figures used to present results must have a strong visual impact and must be simple. The following types of figures are used: line graph, scatter-gram, bar graph, histogram, and the frequency polygon. The title of the figure should reflect its contents. It must be labeled correctly. Symbols must be defined. The names of variables and units of measurement must be labeled appropriately. Tables must be properly titled and column headings clearly indicated. Footnotes, subscripts, and superscripts can be used.
The discussion section states the research hypothesis, answers it, and supports the answers using data from the current study and other studies. It provides reasons to show that the answer to the question is reasonable. It explores and explains possible sources of error and bias. It also identifies and explains differences between the study results and published results. As part of intellectual honesty it discusses the strengths as well as the weaknesses of the study and how they impact on the interpretation of the results. Issues of validity and precision are also addressed. Also discussed is whether the result is new and how important it is.
References are used to acknowledge information obtained from others. The references must be the most recent and most easily available on the subject. Review articles are better than original articles. They may be journal articles, books, PhD theses, abstracts of meetings, or conference proceedings. The reference should be put immediately after the relevant text. If there are several references in a sentence, cite each reference at the relevant point and do not wait to put all of them at the end of the sentence. References should be written using the Vancouver style which is: Author. Title. Journal Year; Volume (number): starting page – ending page.
