Writing the Experimental Report: Overview, Introductions, and Literature Reviews
Written for undergraduate students and new graduate students in psychology (experimental), this handout provides information on writing in psychology and on experimental report and experimental article writing.
Contributors:Dana Lynn Driscoll, Aleksandra Kasztalska
Last Edited: 2013-03-11 09:54:55
Experimental reports (also known as "lab reports") are reports of empirical research conducted by their authors. You should think of an experimental report as a "story" of your research in which you lead your readers through your experiment. As you are telling this story, you are crafting an argument about both the validity and reliability of your research, what your results mean, and how they fit into other previous work.
These next two sections provide an overview of the experimental report in APA format. Always check with your instructor, advisor, or journal editor for specific formatting guidelines.
Experimental reports follow a general to specific to general pattern. Your report will start off broadly in your introduction and discussion of the literature; the report narrows as it leads up to your specific hypotheses, methods, and results. Your discussion transitions from talking about your specific results to more general ramifications, future work, and trends relating to your research.
Experimental reports in APA format have a title page. Title page formatting is as follows:
- A running head and page number in the upper right corner (right aligned)
- A definition of running head in IN ALL CAPS below the running head (left aligned)
- Vertically and horizontally centered paper title, followed by author and affiliation
Please see our sample APA title page.
Crafting your story
Before you begin to write, carefully consider your purpose in writing: what is it that you discovered, would like to share, or would like to argue? You can see report writing as crafting a story about your research and your findings. Consider the following.
- What is the story you would like to tell?
- What literature best speaks to that story?
- How do your results tell the story?
- How can you discuss the story in broad terms?
During each section of your paper, you should be focusing on your story. Consider how each sentence, each paragraph, and each section contributes to your overall purpose in writing. Here is a description of one student's process.
Briel is writing an experimental report on her results from her experimental psychology lab class. She was interested in looking at the role gender plays in persuading individuals to take financial risks. After her data analysis, she finds that men are more easily persuaded by women to take financial risks and that men are generally willing to take more financial risks.
When Briel begins to write, she focuses her introduction on financial risk taking and gender, focusing on male behaviors. She then presents relevant literature on financial risk taking and gender that help illuminate her own study, but also help demonstrate the need for her own work. Her introduction ends with a study overview that directly leads from the literature review. Because she has already broadly introduced her study through her introduction and literature review, her readers can anticipate where she is going when she gets to her study overview. Her methods and results continue that story. Finally, her discussion concludes that story, discussing her findings, implications of her work, and the need for more research in the area of gender and financial risk taking.
The abstract gives a concise summary of the contents of the report.
- Abstracts should be brief (about 100 words)
- Abstracts should be self-contained and provide a complete picture of what the study is about
- Abstracts should be organized just like your experimental report—introduction, literature review, methods, results and discussion
- Abstracts should be written last during your drafting stage
The introduction in an experimental article should follow a general to specific pattern, where you first introduce the problem generally and then provide a short overview of your own study. The introduction includes three parts: opening statements, literature review, and study overview.
Opening statements: Define the problem broadly in plain English and then lead into the literature review (this is the "general" part of the introduction). Your opening statements should already be setting the stage for the story you are going to tell.
Literature review: Discusses literature (previous studies) relevant to your current study in a concise manner. Keep your story in mind as you organize your lit review and as you choose what literature to include. The following are tips when writing your literature review.
- You should discuss studies that are directly related to your problem at hand and that logically lead to your own hypotheses.
- You do not need to provide a complete historical overview nor provide literature that is peripheral to your own study.
- Studies should be presented based on themes or concepts relevant to your research, not in a chronological format.
- You should also consider what gap in the literature your own research fills. What hasn't been examined? What does your work do that others have not?
Study overview: The literature review should lead directly into the last section of the introduction—your study overview. Your short overview should provide your hypotheses and briefly describe your method. The study overview functions as a transition to your methods section.
You should always give good, descriptive names to your hypotheses that you use consistently throughout your study. When you number hypotheses, readers must go back to your introduction to find them, which makes your piece more difficult to read. Using descriptive names reminds readers what your hypotheses were and allows for better overall flow.
In our example above, Briel had three different hypotheses based on previous literature. Her first hypothesis, the "masculine risk-taking hypothesis" was that men would be more willing to take financial risks overall. She clearly named her hypothesis in the study overview, and then referred back to it in her results and discussion sections.
Thais and Sanford (2000) recommend the following organization for introductions.
- Provide an introduction to your topic
- Provide a very concise overview of the literature
- State your hypotheses and how they connect to the literature
- Provide an overview of the methods for investigation used in your research
Bem (2006) provides the following rules of thumb for writing introductions.
- Write in plain English
- Take the time and space to introduce readers to your problem step-by-step; do not plunge them into the middle of the problem without an introduction
- Use examples to illustrate difficult or unfamiliar theories or concepts. The more complicated the concept or theory, the more important it is to have clear examples
- Open with a discussion about people and their behavior, not about psychologists and their research
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An APA-style paper includes the following sections: title page, abstract, introduction, method, results, discussion, and references. Your paper may also include one or more tables and/or figures. Different types of information about your study are addressed in each of the sections, as described below.
General formatting rules are as follows:
- Do not put page breaks in between the introduction, method, results, and discussion sections.
- The title page, abstract, references, table(s), and figure(s) should be on their own pages.
- The entire paper should be written in the past tense, in a 12-point font, double-spaced, and with one-inch margins all around.
(see sample on p. 41 of APA manual)
- Title should be between 10-12 words and should reflect content of paper (e.g., IV and DV).
- Title, your name, and Hamilton College are all double-spaced (no extra spaces)
- Create a page header using the “View header” function in MS Word. On the title page, the header should include the following:
- Flush left: Running head: THE RUNNING HEAD SHOULD BE IN ALL CAPITAL LETTERS. The running head is a short title that appears at the top of pages of published articles. It should not exceed 50 characters, including punctuation and spacing. (Note: on the title page, you actually write the words Running head, but these words do not appear on subsequent pages; just the actual running head does. If you make a section break between the title page and the rest of the paper you can make the header different for those two parts of the manuscript).
- Flush right, on same line: page number. Use the toolbox to insert a page number, so it will automatically number each page.
(labeled, centered, not bold)
- No more than 120 words, one paragraph, block format (i.e., don’t indent), double-spaced.
- State topic, preferably in one sentence. Provide overview of method, results, and discussion
(Do not label as “Introduction.” Title of paper goes at the top of the page—not bold)
The introduction of an APA-style paper is the most difficult to write. A good introduction will summarize, integrate, and critically evaluate the empirical knowledge in the relevant area(s) in a way that sets the stage for your study and why you conducted it. The introduction starts out broad (but not too broad!) and gets more focused toward the end. Here are some guidelines for constructing a good introduction:
- Don’t put your readers to sleep by beginning your paper with the time-worn sentence, Past research has shown....(blah blah blah) They’ll be snoring within a paragraph! Try to draw your reader in by saying something interesting or thought-provoking right off the bat. Take a look at articles you’ve read. Which ones captured your attention right away? How did the authors accomplish this task? Which ones didn’t? Why not? See if you can use articles you liked as a model. One way to begin (but not the only way) is to provide an example or anecdote illustrative of your topic area.
- Although you won’t go into the details of your study and hypotheses until the end of the intro, you should foreshadow your study a bit at the end of the first paragraph by stating your purpose briefly, to give your reader a schema for all the information you will present next.
- Your intro should be a logical flow of ideas that leads up to your hypothesis. Try to organize it in terms of the ideas rather than who did what when. In other words, your intro shouldn’t read like a story of “Schmirdley did such-and-such in 1991. Then Gurglehoff did something-or-other in 1993. Then....(etc.)” First, brainstorm all of the ideas you think are necessary to include in your paper. Next, decide which ideas make sense to present first, second, third, and so forth, and think about how you want to transition between ideas. When an idea is complex, don’t be afraid to use a real-life example to clarify it for your reader. The introduction will end with a brief overview of your study and, finally, your specific hypotheses. The hypotheses should flow logically out of everything that’s been presented, so that the reader has the sense of, “Of course. This hypothesis makes complete sense, given all the other research that was presented.”
- When incorporating references into your intro, you do not necessarily need to describe every single study in complete detail, particularly if different studies use similar methodologies. Certainly you want to summarize briefly key articles, though, and point out differences in methods or findings of relevant studies when necessary. Don’t make one mistake typical of a novice APA-paper writer by stating overtly why you’re including a particular article (e.g., “This article is relevant to my study because…”). It should be obvious to the reader why you’re including a reference without your explicitly saying so. DO NOT quote from the articles, instead paraphrase by putting the information in your own words.
- Be careful about citing your sources (see APA manual). Make sure there is a one-to-one correspondence between the articles you’ve cited in your intro and the articles listed in your reference section.
- Remember that your audience is the broader scientific community, not the other students in your class or your professor. Therefore, you should assume they have a basic understanding of psychology, but you need to provide them with the complete information necessary for them to understand the research you are presenting.
(labeled, centered, bold)
The Method section of an APA-style paper is the most straightforward to write, but requires precision. Your goal is to describe the details of your study in such a way that another researcher could duplicate your methods exactly. The Method section typically includes Participants, Materials and/or Apparatus, and Procedure sections. If the design is particularly complicated (multiple IVs in a factorial experiment, for example), you might also include a separate Design subsection or have a “Design and Procedure” section. Note that in some studies (e.g., questionnaire studies in which there are many measures to describe but the procedure is brief), it may be more useful to present the Procedure section prior to the
Materials section rather than after it.
(labeled, flush left, bold)
- Total number of participants (# women, # men), age range, mean and SD for age, racial/ethnic composition (if applicable), population type (e.g., college students). Remember to write numbers out when they begin a sentence.
- How were the participants recruited? (Don’t say “randomly” if it wasn’t random!) Were they compensated for their time in any way? (e.g., money, extra credit points)
- Write for a broad audience. Thus, do not write, “Students in Psych. 280...” Rather, write (for instance), “Students in a psychological statistics and research methods course at a small liberal arts college….”
- Try to avoid short, choppy sentences. Combine information into a longer sentence when possible.
(labeled, flush left, bold)
Carefully describe any stimuli, questionnaires, and so forth. It is unnecessary to mention things such as the paper and pencil used to record the responses, the data recording sheet, the computer that ran the data analysis, the color of the computer, and so forth. If you included a questionnaire, you should describe it in detail. For instance, note how many items were on the questionnaire, what the response format was (e.g., a 5-point Likert-type scale ranging from 1 (strongly disagree) to 5 (strongly agree)), how many items were reverse-scored, whether the measure had subscales, and so forth. Provide a sample item or two for your reader. If you have created a new instrument, you should attach it as an Appendix. If you presented participants with various word lists to remember or stimuli to judge, you should describe those in detail here. Use subheadings to separate different types of stimuli if needed. If you are only describing questionnaires, you may call this section “Measures.”
(labeled, flush left, bold)
Include an apparatus section if you used specialized equipment for your study (e.g., the eyetracking machine) and need to describe it in detail.
(labeled, flush left, bold)
What did participants do, and in what order? When you list a control variable (e.g., “Participants all sat two feet from the experimenter.”), explain WHY you did what you did. In other words, what nuisance variable were you controlling for? Your procedure should be as brief and concise as possible. Read through it. Did you repeat yourself anywhere? If so, how can you rearrange things to avoid redundancy? You may either write the instructions to the participants verbatim or paraphrase, whichever you deem more appropriate. Don’t forget to include brief statements about informed consent and debriefing.
(labeled, centered, bold)
In this section, describe how you analyzed the data and what you found. If your data analyses were complex, feel free to break this section down into labeled subsections, perhaps one section for each hypothesis.
- Include a section for descriptive statistics
- List what type of analysis or test you conducted to test each hypothesis.
- Refer to your Statistics textbook for the proper way to report results in APA style. A t-test, for example, is reported in the following format: t (18) = 3.57, p < .001, where 18 is the number of degrees of freedom (N – 2 for an independentgroups t test). For a correlation: r (32) = -.52, p < .001, where 32 is the number of degrees of freedom (N – 2 for a correlation). For a one-way ANOVA: F (2, 18) = 7.00, p < .001, where 2 represents the dfbetween and 18 represents dfwithin. Remember that if a finding has a p value greater than .05, it is “nonsignificant,” not “insignificant.” For nonsignificant findings, still provide the exact p values. For correlations, be sure to report the r2 value as an assessment of the strength of the finding, to show what proportion of variability is shared by the two variables you’re correlating. For t- tests and ANOVAs, report eta2.
- Report exact p values to two or three decimal places (e.g., p = .042; see p. 114 of APA manual). However, for pvalues less than .001, simply put p < .001.
- Following the presentation of all the statistics and numbers, be sure to state the nature of your finding(s) in words and whether or not they support your hypothesis (e.g., “As predicted, …”). This information can typically be presented in a sentence or two following the numbers (within the same paragraph). Also, be sure to include the relevant means and SDs.
- It may be useful to include a table or figure to represent your results visually. Be sure to refer to these in your paper (e.g., “As illustrated in Figure 1…”). Remember that you may present a set of findings either as a table or as a figure, but not as both. Make sure that your text is not redundant with your tables/figures. For instance, if you present a table of means and standard deviations, you do not need to also report these in the text. However, if you use a figure to represent your results, you may wish to report means and standard deviations in the text, as these may not always be precisely ascertained by examining the figure. Do describe the trends shown in the figure.
- Do not spend any time interpreting or explaining the results; save that for the Discussion section.
(labeled, centered, bold)
The goal of the discussion section is to interpret your findings and place them in the broader context of the literature in the area. A discussion section is like the reverse of the introduction, in that you begin with the specifics and work toward the more general (funnel out). Some points to consider:
- Begin with a brief restatement of your main findings (using words, not numbers). Did they support the hypothesis or not? If not, why not, do you think? Were there any surprising or interesting findings?
- How do your findings tie into the existing literature on the topic, or extend previous research? What do the results say about the broader behavior under investigation? Bring back some of the literature you discussed in the Introduction, and show how your results fit in (or don’t fit in, as the case may be). If you have surprising findings, you might discuss other theories that can help to explain the findings. Begin with the assumption that your results are valid, and explain why they might differ from others in the literature.
- What are the limitations of the study? If your findings differ from those of other researchers, or if you did not get statistically significant results, don’t spend pages and pages detailing what might have gone wrong with your study, but do provide one or two suggestions. Perhaps these could be incorporated into the future research section, below.
- What additional questions were generated from this study? What further research should be conducted on the topic? What gaps are there in the current body of research? Whenever you present an idea for a future research study, be sure to explain why you think that particular study should be conducted. What new knowledge would be gained from it? Don’t just say, “I think it would be interesting to re-run the study on a different college campus" or "It would be better to run the study again with more participants.” Really put some thought into what extensions of the research might be interesting/informative, and why.
- What are the theoretical and/or practical implications of your findings? How do these results relate to larger issues of human thoughts, feelings, and behavior? Give your readers “the big picture.” Try to answer the question, “So what?”
- Final paragraph: Be sure to sum up your paper with a final concluding statement. Don’t just trail off with an idea for a future study. End on a positive note by reminding your reader why your study was important and what it added to the literature.
(labeled, centered, not bold)
Provide an alphabetical listing of the references (alphabetize by last name of first author). Double-space all, with no extra spaces between references. The second line of each reference should be indented (this is called a hanging indent and is easily accomplished using the ruler in Microsoft Word). See the APA manual for how to format references correctly. Examples of references to journal articles start on p. 198 of the manual, and examples of references to books and book chapters start on pp. 202. Digital object identifiers (DOIs) are now included for electronic sources (see pp. 187-192 of APA manual to learn more).
Journal article example:
[Note that only the first letter of the first word of the article title is capitalized; the journal name and volume are italicized. If the journal name had multiple words, each of the major words would be capitalized.]
Ebner-Priemer, U. W., & Trull, T. J. (2009). Ecological momentary assessment of mood disorders and mood dysregulation. Psychological Assessment, 21, 463-475. doi:10.1037/a0017075
Book chapter example:
[Note that only the first letter of the first word of both the chapter title and book title are capitalized.]
Stephan, W. G. (1985). Intergroup relations. In G. Lindzey & E. Aronson (Eds.), The handbook of social psychology (3rd ed., Vol. 2, pp. 599-658). New York: Random House.
Gray, P. (2010). Psychology (6th ed.). New York: Worth
There are various formats for tables, depending upon the information you wish to include. See the APA manual. Be sure to provide a table number and table title (the latter is italicized). Tables can be single or double-spaced.
If you have more than one figure, each one gets its own page. Use a sans serif font, such as Helvetica, for any text within your figure. Be sure to label your x- and y-axes clearly, and make sure you’ve noted the units of measurement of the DV. Underneath the figure provide a label and brief caption (e.g., ―Figure 1. Mean evaluation of job applicant qualifications as
a function of applicant attractiveness level‖). The figure caption typically includes the IVs/predictor variables and the DV. Include error bars in your bar graphs, and note what the bars represent in the figure caption: Error bars represent one standard error above and below the mean.
(see pp. 174-179 of APA manual)
When citing sources in your paper, you need to include the authors’ names and publication date. You should use the following formats:
When including the citation as part of the sentence, use AND: “According to Jones and Smith (2003), the…”
When the citation appears in parentheses, use “&”: “Studies have shown that priming can affect actual motor behavior (Jones & Smith, 2003; Klein, Bailey, & Hammer, 1999).” The studies appearing in parentheses should be ordered alphabetically by the first author’s last name, and should be separated by semicolons.
If you are quoting directly (which you should avoid), you also need to include the page number.
For sources with three or more authors, once you have listed all the authors’ names, you may write “et al.” on subsequent mentions. For example: “Klein et al. (1999) found that....” For sources with two authors, both authors must be included every time the source is cited. When a source has six or more authors, the first author’s last name and “et al.” are used every time the source is cited (including the first time).
“Secondary source” is the term used to describe material that is cited in another source. If in his article entitled “Behavioral Study of Obedience” (1963), Stanley Milgram makes reference to the ideas of Snow (presented above), Snow (1961) is the primary source, and Milgram (1963) is the secondary source. Try to avoid using secondary sources in your
papers; in other words, try to find the primary source and read it before citing it in your own work. If you must use a secondary source, however, you should cite it in the following way:
Snow (as cited in Milgram, 1963) argued that, historically, the cause of most criminal acts...
The reference for the Milgram article (but not the Snow reference) should then appear in the reference list at the end of your paper.