MaryAnn Foote, PhD
(CHEST 2009; 135:866–868)
Key words: manuscripts; medical writing; science writing
Scientific manuscripts are structured using the introduction, methods and materials, results, and discussion (or IMRaD) format. For certain types of manuscripts, such as randomized, controlled clinical trials, additional guidelines exist.1 Scientific manuscripts also have abstracts and references. During the past 2 years, in this "Medical Writing Tips" series, we have explored the organization of the abstract, introduction, and methods and materials sections of the manuscript.
This article will discuss the remaining two sections of a research article, results and discussion. These are often the most difficult sections to write clearly and concisely. I will be using the same fictional study as presented in earlier articles2– 4 to illustrate how the entire manuscript flows logically. Again, I caution, I am offering suggestions and food for thought, not a template, for manuscripts based on clinical hypothesis-testing trials.
- The abstract, in a sense, is an abbreviated paper with a format that parallels the full paper. Abstracts can be structured or unstructured.2
- The introduction gives the background to the
subject, provides the gap in the literature, and,
most importantly, asks the research question.3
- The materials and methods section includes the prospectively defined end points or outcome measures and provides enough information for an investigator in the same field to replicate the published work.4
The function of the results section is to provide the results for all end points and measures stated in the materials and methods (or patients and methods) section. The results section of a clinical hypothesistesting manuscript typically includes tables and figures for presenting detailed data in as compact and readily understood a form as possible and is usually devoid of references. The results section should report the results of your study only.
One of the most common problems with the results section occurs when an author provides data but no results, or results but no data. Data are numbers, often best presented in a table or figure. The text of the results section gives meaning to the data, but without "excuses." When reporting results, just provide the facts; discussion and explanation of why results are different than expected belong in the discussion section. The discussion section will also provide a forum for explaining why the results are different from what the researchers had hoped for, either good or bad.
Another potential problem in writing the results section is failure to report all end points that were listed in the materials and methods (or patients and methods) section. Every method must have a result and, conversely, every result must have a method. Results should be reported in the same order as the methods for them were given.5 Include only results of the prespecified end points; ad hoc analyses are not permitted.
What does a good results section look like? The following sections contain my fictional example, which includes some of the most important items required in the results section, along with my brief comments in parentheses. In a real research paper, many of these points would be expanded with more statistical data provided than the few fictional results given. Remember, the materials and methods section has subsections, generally patients, study design, study drugs/interventions, study end points, and statistical analysis.4 All of these sections should appear in the results section. The statistical analysis section, however, is not a free-standing entity here, but all measures predefined in the statistical analysis section (mean, median, range, and 95% confidence interval, for example) would be provided in the appropriate sections (eg, patients and study end points sections).
First Section: Patients
A total of 315 patients were randomly assigned to
treatment, and all patients received at least one dose
of a blinded study drug (drug N, n = 156; drug S,
n = 155)[Fig 1]. The groups were well matched for
baseline characteristics of demography, disease history,
disease severity, and previous radiation (Table
1). The patient population was predominantly men
(76%) and white (66%), and the mean age was 52 years.
Thirty-three patients did not complete the study and
withdrew after withdrawal of consent (n = 11), death
(n = 3), or other adverse events (n = 19).
(In this section, I provided not only the total
number of patients but also the number of patients
assigned to each treatment group. Figure 1 would
show the CONSORT Group Flow Diagram,1 the use
of which allows the reader to quickly grasp the fate of
the patients in terms of their progression through the
study. Table 1 would provide baseline demographic
and clinical information, and should be formatted to
allow easy comparison between the two treatment
groups in this study. This section might also include
the number of patients in each group who completed
each of the proposed five 14-day cycles. This information
would also be provided in the CONSORT
diagram. I have included information on the number
of patients who did not complete the study and will
elaborate on death and withdrawals due to adverse
events in the safety end point section.)
Second Section: Efficacy End Points
The time to progression, the primary efficacy end
point, was 4 months for patients who received drug
N compared with 1 month for patients who received
drug S (p < 0.001)[Table 2]. Overall survival, a
secondary efficacy end point, also was longer for
patients who received drug N compared with patients
who received drug S (22 vs 18 months, respectively;
p < 0.01)[Table 3]. Treatment with drug N
reduced the need for palliative radiation when compared
with treatment with drug S (2% vs 10%,
respectively; p < 0.001)[Table 4].
(In this section, I reported the results of the
primary end point and two secondary efficacy end
points. More information would be provided in the
referenced tables, such as the 95% confidence interval.
Some data might be better showcased in a figure
rather than in a table.)
Third Section: Safety End Points
Reported adverse events were similar between
the two treatment groups, and the adverse events
reported were typical of those in a patient population
with advanced NSCLC who were receiving
treatment with biological therapies (ie, fever, flulike
symptoms, or skin rash) and occurred in
similar proportions of patients in each group
during the study. Most events were of mild or
moderate intensity (Table 5).
During the study, 19 patients withdrew because of
adverse events (drug N, n = 9 [5.8%]; drug S,
n = 10 [6.5%]). The primary reason for study withdrawal
was disease progression (drug N, n = 2
[1.3%]; drug S, n = 4 [2.5%]). One patient treated
with drug N died, and two patients treated with drug
S died; all three deaths were attributed to disease
progression and not to the study drug.
No substantial changes from baseline were noted
in the serum chemistry analytes alkaline phosphatase,
alanine transaminase, aspartate transaminase,
lactic dehydrogenase, or uric acid (data not shown).
(In this section, I have given the results for the two
safety end points, adverse events [which include death],
and changes in laboratory values. If no clinically significant
changes occur, it is acceptable to state this result
and not provide the data in tabular format.)
The function of the discussion section is to discuss how the results answer and support the research question posed in the introduction and to compare and contrast the results with other studies in the field.
The discussion section is fraught with potential
problems. It is the most difficult section of the hypothesis-testing paper to write. Often, the discussion
section dissolves into a repetition of the results
and the introduction of new and inappropriate information,
such as additional or repeated background
information (from the introduction), ad hoc analyses,
and discussion of unrelated studies. The discussion is
meant to include only information relevant to the
current study. The discussion section rarely has
tables or figures, but should contain references, as
references are the way scientists validate their work
and credit the work of other scientists properly.6
Although subsections can be used for structuring
complicated discussion sections, subsections stop the
flow of the writing, so it is better to write using
transitions for moving between and relating ideas.
The main function of the discussion section is to
answer the research question posed in the introduction
and to use the results to support that answer.
The cleanest way to start the discussion and to
answer the research question is by stating, "The
results of our study suggest . . . . . ." or something of
that nature. The topic does not need to be reviewed
again, nor do the results need to be presented again;
however, the author should use the results (and may
refer to a specific table or figure) to support and
explain the answer. It is always acceptable to remind
the audience of the uniqueness or newness of your
data (as first suggested in the introduction). It is
generally wise, however, to avoid the claim of being
first (ie, same or similar work may have been reported
in an article published in another country and
in a language other than English; modesty is always
a good virtue to emulate).
In the "middle" portion of the discussion, you
should discuss your results as they relate to other
work in the field. Any conflicting or unexpected
results should be explained, and limitations for the
study should always be given (ie, the results are
appropriate only for the small patient population
studied, not all patients at large).
It is tempting, particularly when the results are not
as robust as one had hoped for, to provide the results
of ad hoc analyses. However, remember, no new
data can be introduced in the discussion section. If
the results were not as expected, it may be disappointing,
but not a sign of failure. Reporting the
results as obtained from the original hypothesis may
allow you or another group to refine the hypothesis
and proceed with more testing.
Finally, the discussion should end with a good
sentence that summarizes the study, such as, "Thus,
the results of our study suggest that drug N has a
clear clinical advantage over drug S, including a
statistically significant increase in time to progression
and overall survival coupled with an acceptable
safety profile for drug N." Often, I see concluding
sentences that say something like, "The results of this
study suggest that more work needs to be done."
These sorts of sentences bewilder me, as the hypothesis
that was tested, the end points, and the statistical
analyses had nothing to do with the concept of requiring
further testing. Avoid these types of sentences.
The results section simply reports the findings of
the study, and uses tables and figures to compare and
contrast (or at least to organize) data, but the proof of
the pudding, as it were, is in the discussion. A careful
author will ensure that only results are presented for
which there was a corresponding method and that
only the results of the current study are presented as
per the prespecified analysis.
The discussion section requires careful organization,
writing, and editing to ensure that no new
topics are introduced, that the limitations of the
study are included, and that the section does not
become a repeat of the results section without
explanation of what the data mean or how they add
to the body of scientific knowledge. No excuses
should be offered for unexpected data.
So, the proof of the pudding is in the eating: in other
words, results count. Being able to present the results
succinctly and discuss them logically will help produce
an hypothesis-testing paper worthy of publication.
ACKNOWLEDGMENT: I have been honored and humbled to
have had the opportunity to contribute this series of articles to
CHEST. My most heartfelt thanks go to Dr. Patrick Barron, who
engaged me in this project and offered good counsel and
encouragement; the editorial staff at CHEST, particularly Dr.
Richard S. Irwin, Editor in Chief, for their help; and my writer
colleagues who graciously reviewed my work and saved me from
myself in many instances. For this article, I thank Tim Peoples;
Marianne Mallia, ELS; Susan Siefert, ELS, CBC; and Jim Yuen
for comments that added clarity.
- CONSORT. The CONSORT statement. Available at: http://
www.consort-statement.org/. Accessed December 8, 2008
- Foote MA. Some concrete ideas about manuscript abstracts.
Chest 2006; 129:1375–1377
- Foote MA. How to make a good first impression: a proper
introduction. Chest 2006; 130:1935–1937
- Foote MA. Materials and methods: a recipe for success. Chest
- Foote MA. A simple way to write, edit, or review clinical
manuscripts to ensure logical and uniform presentation of
data. AMWA J 2005; 20:123–124
- Foote MA. Why references: giving credit and growing the
field. Chest 2007; 132:344–346
*From MA Foote Associates, Westlake Village, CA.
The author has reported to the ACCP that no significant conflicts
of interest exist with any companies/organizations whose products
or services may be discussed in this article.
Manuscript received November 2, 2008; revision accepted
November 12, 2008.
Reproduction of this article is prohibited without written permission
from the American College of Chest Physicians (www.chestjournal.
Correspondence to: MaryAnn Foote, PhD; e-mail: fmawriter@