Writing an Empirical Paper in APA Style

For descriptions of how to do further subdivisions, see the APA Manual.Tables and Figures. For student papers, either place these at the end of the paper (formal APA style) orincorporate them into the text; ask your instructor.How To Proceed• The hypotheses, methods and results are the easiest to write because they are the most concrete, so you maywant to write these first. The introduction and discussion are often written next. The title and abstract usuallycome last.• Make sure that all the sections are well integrated. Start by finding your hypotheses in the introduction andmaking sure that they are clearly stated. Then see whether each hypothesis is addressed, usually in the sameorder, in the Results and Discussion.• Pay attention to scientific terminology. Scientific reports don't sound like essays or news stories. They aremore condensed and use more precise language. For example, we cannot "prove" theories in science (we givesupporting evidence or fail to find such evidence). Similarly, avoid adverbs (e.g., "really", "very","surprisingly"); they are not quantitative and therefore add no information. See also our handout, Style Pointsfor Scientific Writing.• Check tables and figures (graphs) for accuracy and captions for specificity.• Check for spelling and typographical errors. Don't rely only on spell checkers; they often miss errors (e.g.,affect/effect, its/it's).• Proofread. Ask at least one other person to read what you have written; they will catch things that you miss.Title PageThe title page announces the title and running head of a lab report or research article. It gives the article title,author name(s), author affiliation, manuscript page header, running head and page number.How to Proceed1. Arrange the title page information on its own page. Center this information from the side margins. Place thetitle a little more than one-third of the way down the page, where the reader's eyes naturally fall.Note: The APA manual says to center the title. This means to center from the sides, not from the top.2. Choose a title thoughtfully (see below). Even if you change it later, a descriptive title will help you to stay ontrack as you write your paper and will convey a good first impression to your readers.• Make the title specific.NOT: The Effects of Language Complexity on Mental ProcessingBUT: The Effects of Sentence Complexity on Mental Processing SpeedNOT: Can Stress Predict Memory Accuracy?BUT: Can Stress Level Predict the Accuracy of Eyewitness Accounts?• Try to make a statement or ask a question.Categorical Discrimination Begins at BirthCan the Yerkes-Dodson Law Predict Human Performance?• Consider including the independent variable (IV) and dependent variable (DV) (and perhaps eventhe outcome if it is straightforward).Copyright 1997-2004, University of Washington04/21/04APApaper.pdf

Procedure. Each subsection should provide only the essential information needed to understand andreasonably replicate the experiment. Very short subsections can be combined (e.g., Stimuli and Equipment).There is no APA rule on the order of subsections. The order shown below is common.How to ProceedSubjects/Participants. State the number of participants (if human) or subjects (if animals), who they were,and how they were selected.ParticipantsWe randomly selected 16 University of Washington students from an introductory psychology course to participate in exchangefor extra credit.SubjectsSubjects were 30 male pigtailed macaques (Macaca nemestrina) bred at the Washington Regional Primate Research CenterBreeding Colony, Medical Lake, Washington. All animals were bred specifically for this project and were shipped to thelaboratory at 3-5 days of age. We randomly assigned subjects to each condition.Materials. This subsection may also be called Stimuli, Equipment, or Apparatus. It briefly describes theequipment/materials used in the experiment.Eye movements were recorded using an NEC model 120 Eyetracker.Design. Identify and explain variables and their levels, and state whether the variables are between groups orwithin subjects.The design was a mixed model with type of information requested, type of emotion, and sex as the between-subjects factors.Heart rate and blood pressure were the within-subjects factors.Procedure. Describe in sequence the procedures used.Subjects were seated at a computer work station. After completing a demographic questionnaire, they received writteninstructions that differed by condition. All subjects were instructed to read a business letter and write a reply. Subjects in themultiple draft condition were told to write an outline of a reply letter before writing a final draft.ResultsThis section presents the statistical analysis of the data collected. It is often less than a page long.RequirementsCondensed format. The Results section is the most condensed and standardized of all the sections in the textof a lab report.No data interpretation. Statistical results are presented but are usually not discussed in this section. Discussresults in the Discussion section.How to Proceed• Keep your hypotheses in mind while you write. Each result must refer to a stated hypothesis.• Describe all results that are directly related to your research questions or hypotheses. Start with hypothesesyou were able to support with significant statistics before reporting nonsignificant trends. Then describe anyadditional results that are more indirectly relevant to your questions.• If you present many results (i.e., many variables or variables with many levels), write a brief summary, thendiscuss each variable in separate subsections.• Report main effects before reporting contrasts or interactions. Briefly mention problems such as reasons formissing data, but save discussion of the problems for the discussion section.Copyright 1997-2004, University of Washington04/21/04APApaper.pdf

• Use tables and figures to summarize data. Include descriptive statistics (such as means and standarddeviations or standard errors), and give significance levels of any inferential statistics. The goal is to makeyour results section succinct and quantitatively informative, with no extra words (see also our handout, APATable Guidelines).• For each test used, provide degrees of freedom, obtained value of the test, and the probability of the resultoccurring by chance (p-value). Here are examples of the results of a t-test and an F-test, respectively: t(23)=101.2, p < .001; F(1,3489) = 7.943, p < .001 (see also our handout Reporting statistical results in APAformat).DiscussionIn this section, interpret your results by relating them to your hypotheses. Use words to explain the quantitativeinformation from the results section.RequirementsDiscuss the results in relation to each hypothesis. This is the most important part of the Discussion section.Discuss possible explanations for your results. This part should follow from the predictions you madeearlier based on possible outcomes of the study. Do the results agree or disagree with the ideas that youintroduced in the Introduction? How do the results relate to previous literature or current theory? Identify anddiscuss limitations in the experimental design that may reduce the strength of your results. Generalize yourresults. This is where you tell the reader the extent to which your study is externally valid. Discuss strengthsand weaknesses of applying your results to, for example, another population, species, age, or sex.Identify followup experiments. Introduce new ideas that your results suggest, and propose ways to test them.How to Proceed• Explain whether your results support the hypotheses.• Discuss how the results relate to the research question in general.The results are consistent with the Yerkes-Dodson law.These results show the advantage of using a secondary reaction time paradigm for assessing cognitive load during reading.The finding that the infant monkeys increased their food intake in the low-calorie condition and reduced food intake in the highcaloriecondition is consistent with the hypothesis that pigtailed macaques adjust their food intake to maintain a constant level ofcaloric intake. Although the difference between the two conditions decreased across time, however, the infants consumed morecalories in the high-calorie condition than the low-calorie condition.• If you had a directional hypothesis and your results didn't turn out as expected, discuss possible explanationsas to why, including unanticipated shortcomings in the design, problems such as equipment failure, or eventhat the theory you tested may need modification. Show how your explanation accounts for the specificpattern of results.NOT: One reason for this puzzling result could be that some subjects received different instructions. Another possible reasonmight be that the room was hot. A third possibility is that we should have . . .This example is not well written for two reasons. First, the reasons are unsupported. The author does notexplain how these reasons may have led to the unexpected pattern of results. Second, probably because of thislack of justification, the author's use of "could" and "should" does not sound confident.BETTER: One possible explanation for this result is that experimental subjects received slightly different instructions thancontrol subjects. Subjects in the control condition were told to press [1] for "yes", but subjects in the experimental condition weretold to press [y] for "yes". Because [1] and [y] are positioned apart on the computer keyboard, the extra time required to find [y]Copyright 1997-2004, University of Washington04/21/04APApaper.pdf

may account for the overall longer reaction time in the experimental condition. Another unexpected variable was that theventilation in the room malfunctioned and the room was over 75 0 F. Although this made the test situation uncomfortable, theroom temperature affected all subjects equally, so we do not regard this extraneous variable as a confound, but it could haveaffected the validity of the results if subjects performed more poorly as a result.Discuss limitations of the experiment that could be remedied in future experiments. State the specific reasonfor performing the next experiment. Do not assume that anything is obvious.Although we controlled the level of subject arousal, we did not control the type of arousal (negative or positive). A future studyin which we assessed the effects of negative versus positive arousal on eyewitness accuracy would enable us to refine Yerkes-Dodson predictions.• Avoid overstating the importance of your findings. Be modest rather than expansive. Avoid speculatingbeyond the data.• Stay focused on the research question. Resist the urge to digress or to state glittering generalities just becausethis section is the most flexible one.• Although you should acknowledge problems or weaknesses of your design, end the paper on a high note.Summarize the study’s strengths, conclusions, implications and/or ideas for future research.ReferencesBelow are the most common citation styles used for writing lab reports (see also pp. 194-221 of the APA Manual,5th ed., and our APA citations handout).RequirementsUse APA format unless instructed to do otherwise. Capitalization, spacing, punctuation, and underliningmust be exactly as specified. Correct APA style is important because it will make your paper easier to readand help you to present information accurately. Keep in mind that publishers convert APA-formattedmanuscripts into the specific format used in their journal (and non-APA journals may not even use APAstyle), so don't just copy a style that you see in a journal.How to Proceed• List all authors cited in the text in alphabetical order. Do not list authors that you did not cite in the text, orcite authors of primary citations when you read only the secondary citation (see APA citations).• Use the correct citation format for each source (see examples below, the APA manual, or APA citations).• Double-space each citation, indenting each line after the first (hanging indent). Instructors may allow olderformats, or single spacing with a double space between references, but this is not APA format.Examples:Journal with one author:Sanders, G. P. (1990). Animal models of discrimination learning. Journal of Learning and Behavior, 81, 635 - 647.Journal with two or more authors:Book:Becker, L. J., & Seligman, C. (1996). Infant social behavior: Developmental issues. The Development of Children, 5, 1 - 43.Bernstein, T. M. (1965). The careful writer: A modern guide to English usage. New York: Atheneum.A study cited within a later study (secondary citation):Copyright 1997-2004, University of Washington04/21/04APApaper.pdf

Smith (cited in Jones, 1996) argued that …The example above refers to a 1996 paper by Jones (which you read), in which Jones cited a 1954 paper bySmith (which you did not read). Always try to read the original article (see APA citations for an explanation).If you think that you must refer to Smith's study, but you are unable to read Smith's paper, then cite onlyJones in the reference list. In the text, cite Smith, but not the year of Smith's study, as shown above.Tables and FiguresTables and figures often represent results more clearly and concisely than does text.Requirements (for a more detailed discussion, see APA Manual, 5th ed., pp. 120-162):Captions. All tables and figures require captions. Place table captions above the table. Place figure captionson a separate page from the figure, called the Figure Captions page. If your instructor allows you to putcaptions on the same page as the figure, put the caption under the figure. The caption consists of thetable/figure number in arabic numerals and a clear, specific description of the table or figure. Use completesentences in figure captions.Labels. Number the tables and figures separately.Footnotes. Use footnotes in tables to explain missing data and any other key information that doesn't fit in thetable itself.Align margins. Line up columns of numbers on the decimal points. Line up text along the left margin of acolumn.References to text. Tables and figures are supplements to the text and should not duplicate text. If youinclude a table or figure, you must refer to it in your paper. Refer to tables and figures by their numbers eitherin the text or in parentheses.How to Proceed• To get an idea of the type of content normally included and the formatting used., look at the APA manual orpublished articles for examples of tables and figures.• Tables save more space, but figures have a greater visual impact.• Use tables to summarize data when the information is too wordy for the text (e.g., number of subjects, meansand standard deviations, p-values).• Use figures to help the reader visualize patterns of results.• Design the table or figure to stand alone, as an independent source of information. Captions, variable labels,and value labels should be precisely worded.• Have someone else critique the table or figure for thoroughness and ease of understanding.• Allow time to design tables and figures. They are not easily done at the last minute. Sloppy graphics maketables and figures hard to understand.Other ResourcesAmerican Psychological Association (2001). Publication manual of the American Psychological Association (5thedition). Washington, D.C.: American Psychological Association.Bem, D. J. (1987). Writing the empirical journal article. In M. P. Zanna & J. M. Darley (Eds.), The completeacademic: A practical guide for the beginning social scientist (pp. 171-201). New York: Random House.Copyright 1997-2004, University of Washington04/21/04APApaper.pdf

Kazdin, A. E. (1995). Preparing and evaluating research reports. Psychological Assessment, 7, 228-237.Copyright 1997-2004, University of Washington04/21/04APApaper.pdf

Writing an Empirical Paper in APA Style

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