The IMRaD Model of Dissertation Chapters The Most Important Things to Keep in Mind You need to write three journal-quality experimental reports along with the literature review, these will become the main chapters of your thesis. What I cover is a conventional format for such reports--imrad (Introduction, Materials/Methods, Results, and Discussion)--but you will need to match your format to your discipline. Look at past dissertations and at journals in your field to ensure you use the correct format. Likewise, the your citation format (usually Council of Science Editors, CSE) will depend on your field. What follows is a standardized description of what goes into each section of an experimental report. INTRODUCTION Purpose: to supply sufficient background for your reader to understand and evaluate the results of your experiment; to provide the rationale for your study; to state briefly and clearly your purpose in writing the paper. The introduction to a research report always includes: 1. the nature and scope of the research problem 2. a review of the pertinent literature 3. the method of investigation, possibly with rationale The introduction to a research report usually includes: 4. the principal results 5. the principal conclusions As you write, consider the following questions: How can you grab your reader s attention? Why is this topic important? Of interest? What work has been done on the problem so far? What is the gap in the literature/problem with previous research? (What conflict or unanswered question, untested population, untried method in existing research does your experiment address? What findings of others are you challenging or extending?) What solution (or step toward a solution) do you propose? Briefly describe your experiment: hypothesis(es), research question(s); general experimental design or method; justification of method if alternatives exist. This is not a mystery novel: Give away the ending.
Start writing the introduction while the experiment is underway. Use mostly present tense. Engage your reader by showing context, relative importance, unanswered questions. Make clear links between problem and solution, question asked and research design, prior research and your experiment. Be selective, not exhaustive, in choosing studies to cite and amount of detail to include. In general, the more relevant an article is to your study, the more space it deserves and the later in the introduction it appears. The introduction is the place to mention your own previously published note, abstract or closely related articles put this at or near the end and to define specialized terms (when needed) or abbreviations. METHODS Purpose From the methods section (sometimes methods and materials), the reader should be able to conceptualize and evaluate your process and replicate your work. The section answers the question: How was the data generated? Were results generated in a manner consistent with accepted practice? Were methods appropriate to objectives? What analytical methods were applied? The section includes enough specific detail about materials used and methods followed that another scientist could repeat your experiment, especially to verify your results. This section should also cover the problems you anticipated, the steps you took to prevent them from occurring, the problems that did occur and the ways you minimized their impact. Common Problems Not taking the reader s level of expertise into account: edit for unnecessary explanation of common procedures. Not providing for reproducibility: consider exactly what your reader will need to reproduce your work. The most crucial detail is usually measurement. Not providing rationale for the protocol followed. Not describing the control: identify the control(s) and explain what they are controlling for. Ignoring significant problems: discuss problems that arose and how you overcame them. Putting results in the methods section: results always go in the results section. Process Keep excellent notes: what you did, why you did it, and what happened. As you revise, go to your target publication and read the notes to authors AND the methods sections of several articles similar to yours. Organization Narrative structure: Think of this section as a narrative not a recipe. Tell what you did, not how to perform the experiment. Follow natural chronology: Describe what you did in the order in which you did it. Consider using subsections: if you used a lot of materials, if the procedure is unusually complicated, or if you have used a new or generally unfamiliar procedure.
Mechanics: Tense: use past tense to refer to everything you did during the experiment. Passive vs. active voice: It depends. Check your target publication. RESULTS Function: to objectively present your key results, without interpretation, in an orderly and logical sequence using both illustrative materials (Tables and Figures) and text. Organization: The tables and/or figures present key findings in a logical order. This organization of the tables and figures should tell a story, leading the reader through the steps needed to logically answer the research question. The text of the results section follows this sequence and highlights the answers to the research question. Refer to each Table and/or Figure individually and in sequence (see numbering sequence), and clearly indicate for the reader the key results that each conveys. Key results depend on your question: they might include obvious trends, important differences, similarities, correlations, maximums, minimums, etc. Summarize Data: Reduce data to a manageable size. Convert raw data to means, for example by reporting mean capture rates in weeks or months. Present this compacted information in the visually accessible forms of Tables and Figures. Once reduced, comparisons can be made, trends can be noted, and from them generalizations can be put forth. Both kinds of information must be presented: In the text section, present the major generalization(s); In the Tables and Figures, present the data supporting the generalization(s). Text Section: The body of the Results section is a text-based presentation of the key findings. The text should guide the reader through the results, stressing key findings. A major function of the text section is to provide clarifying information. Write the text of the Results section consecutively, concisely and objectively. Use passive voice if that is the norm of the target journal but use the active voice when possible. Use past tense. Every Figure and Table included in the paper MUST be referred to in the text section; these references should be individual, in sequence and should clearly indicate for the reader the key results that each conveys. Sentences should draw the reader's attention to the relationship or trend highlighted. Refer to the appropriate Figure or Table parenthetically: Germination rates were significantly higher after 24 h in running water than in controls (Fig. 4). DNA sequence homologies for the purple gene from the four congeners (Table 1) show high similarity, differing by at most 4 base pairs. Tables and Figures: These can take 3 forms: text (different than the text section described above), Tables and Figures. Arrange these in the most logical sequence. Text: Some simple results are best stated in a single sentence, with data summarized parenthetically. Figures: Figures are visual presentations of results, including graphs, diagrams, photos, drawings, schematics, maps, etc. Graphs show trends or patterns of relationship. Bar graphs, frequency histograms,
X,Y scatterplot, X,Y linegraphs, photos and gels are all examples of figures. Choose the type according to what is being presented, linegraphs, for example, are useful for showing chronology. Bar graphs show relative magnitudes well. Tables: Tables present lists of numbers or text in columns, each column having a title or label. Do not use a table when you wish to show a trend or a pattern of relationship between sets of values - these are better presented in a Figure. Tables are useful when exact values are important, when using verbal data, or when there are no clear patterns that lend themselves to graphical presentation. Tables and Figures must be clear, well labeled, and described by their legends; they should be easily understood independent of the text section. Use the simplest possible design. Legends (or captions) should convey as much information as possible about the Table or Figure: the subjects of the experiment, the treatment applied or the relationship displayed, location (if a field experiment), and sample sizes and statistical tests if they are not displayed elsewhere. Table legends go above the body of the Table and are left justified; Tables are read from the top down. Figure legends go below the graph; graphs and other types of Figures are usually read from the bottom up. Figures and Tables are numbered independently, in the sequence in which they are referred to in the text, starting with Figure 1 and Table 1. The first Table refered to is Table 1, the next Table 2 and so forth. Similarly, the first Figure is Figure 1, the next Figure 2, etc. When referring to a Figure in the text, the word "Figure" is abbreviated as "Fig.", while "Table" is not abbreviated. Do not reiterate each value from a Figure or Table - only the key result or trends that each conveys. Do not present the same data in both a Table and Figure - this is considered redundant and a waste of space and energy. Decide which format best shows the result and go with it. Do not report raw data values when they can be summarized as means. Do present the results of your experiment(s) in a sequence that will logically support (or provide evidence against) the hypothesis, or answer the question, stated in the Introduction. Do report negative results. Style: concise and objective/ past tense. DISCUSSION Purpose: to interpret your results and explain your new understanding of the problem. Relate your work to the findings of other studies - including previous studies you may have done. Note that some journals separate Discussion and Conclusion; others fold Results and Discussion together. Considerations/Content: Do your results provide answers to your testable hypotheses? Relate discussion back to the objectives and questions raised in the Introduction section. However, do not simply re-state the objectives. Make statements that synthesize all the evidence.
If necessary, note problems with the methods and explain anomalies in the data. Do not simply list the problems but provide thoughtful discussion about the implications of the errors in terms of your conclusions. Do your findings agree with what others have shown or not? Interpret your results in light of other published results, by adding additional information from sources you cited in the Introduction section as well as by introducing new sources. Provide accurate citations. What is our new understanding of the problem posed in the intro? Do not make statements that are too broad. Limit conclusions to those the data support. What is the next step? Suggest future directions for research, new methods, explanations for deviations from previously published results, etc. Organization: follow the sequence established in the results / use subheadings, if needed and if used in your target journals Do not introduce new results in the Discussion. Style: Use the active voice whenever possible in this section. Watch out for wordy phrases; be concise and make your points clearly ABSTRACTS The abstract is a very condensed summary of the hypothesis, methods, results, and conclusions of your report. Consider the purpose and audience for your abstract. It will be read by many more people than will read your paper. It will exist outside of the context of your paper. Its length, form, and content are dictated by discipline and journal. It should: Stand on its own Focus on summarizing results and strictly limit background information Be consistent with what is reported in the paper Be clear, concise and complete Use complete and straightforward sentences. Usually be a single paragraph, but this depends on the discipline and journal. Be written in past tense Avoid: acronyms, abbreviations, citations RESOURCES Day and Gastel, How to Write and Publish a Scientific Paper (Greenwood Press). Penrose and Katz, Writing in the Sciences (Allyn and Bacon) Scientific Style and Format: The CSE Manual for Authors, Editors, and Publishers Seventh Edition http://www.dianahacker.com/resdoc/sciences.ht ml (CSE formatting) Graduate Writing Fellows: writingfellows@ucdavis.edu