1) Use 3 or fewer important elements in each level of an argument.

Often, students report that class assignments involve achieving minimum word or page counts (i.e. a "10 page paper). Students sometimes add unnecessary "filler" text to reach required page counts. However, scientific communication presents the opposite requirement. The goal of scientific communication is to defend arguments and report conclusions using as FEW words as possible. 

Many scientific journals have strict word limits. For example one of the top scientific journals, Science Magazine, has a word limit for research articles of 8,000 words or fewer. 8,000 words is approximately equivalent to a 32-page paper, which may seem like a lot. However, thoroughly explaining the results of studies that involved years of dedicated work by many scientists in the space of 32 pages can be extremely challenging. Therefore, scientists must typically try to defend their scientific conclusions under severe word number constraints.

When space (for written papers) or time (for spoken presentations) are limited, then clearly the number of conclusions that authors can strongly defend is also limited. Defending ONE main conclusion will allow the strongest argument, because the author can devote the entire paper or presentation to defending the single conclusion. Defending additional arguments is, to a certain extent, a "zero sum game." Introducing more elements of information (e.g. premises, conclusions, or concepts) diminishes the emphasis on (and ability to remember) other elements of information. Therefore, it is important to "pick ones' battles" and focus on presenting ONLY the conclusions that can be reasonably defended given space or time constraints. 

However, even if authors seek to defend a SINGLE conclusion (e.g. one general hypothesis), there are usually many elements of evidence that must be organized in supporting arguments. How can authors effectively organize large bodies of supporting evidence? 

The Rule of Three suggests that evidence and arguments that support a conclusion will be strongest if grouped in a hierarchy (such as a tree structure), where each level of the hierarchy has three or fewer supporting elements. 

For example consider a student who seeks to apply to graduate school in Occupational Therapy (OT). The general conclusion that the student seeks to defend is "I am capable of being an outstanding Pediatric Occupational Therapist." However, clearly there are MANY personal attributes and skills that a student could use to demonstrate that they are capable of being an outstanding O.T. How should the student make their statement more specific? How should the student organize examples of their attributes, skills, and experiences to support their more specific conclusions?

The Rule of Three suggests that the student pick three or fewer specific attributes or skills to defend in their personal statement. With a limited number of attributes/skills to defend, the student can focus on making strong, focused arguments to defend each attribute or skill. Suppose that the student chose "empathetic" as an attribute, and "ability to work with diverse populations" and "demonstrated ability to improve performance" as skills:

After starting with the simple hierarchy of three attributes/skills to defend, the student could use the Rule of Three to organize evidence for each of the three sections. For example, for the first section (in outline form):

1) I treat others with empathy even in challenging situations.

     A) I am empathetic to the challenges of others

          Example: Volunteering for 100 hours at Springfield Community Help Organization. Most interactions I had with clients were very positive and rewarding.

               HOWEVER, some clients were agitated and verbally confrontational, tempting me to become angry. [SPECIFIC EXAMPLE].

               Therefore, I learned that people are often experiencing stresses that we don't understand. I learned that asking questions was often a good way to learn about the challenges that other people face. I learned how to respect and empathize with people even when my initial reaction to their apparent attitude might have been anger.

     B) I have learned how to be empathetic even during times when I was challenged.

          Example: Working at Tasty Burger for 20 hours per week for the past three years while being a full-time student. I worked in a fast-paced environment with approximately 20 different teams of individuals.

               HOWEVER, during stressful times like mid-terms and finals, I found it difficult to be understanding when my co-workers called in sick or asked to change their shifts.

               Therefore, I learned to separate work problems from academic stress, and find solutions that were acceptable to both my co-workers and to me.

For each example, the student should make sure that the example supports the overall main conclusion "I am capable of being an outstanding Pediatric Occupational Therapist."

The example of the student's personal statement is fabricated, and would clearly be different for everyone. However, the example illustrates that the Rule of Three can help to organize arguments and to LIMIT the information presented to readers to only information that clearly contribute to defending a single conclusion. 

To make the strongest arguments possible, and to prevent audiences from being overwhelmed with information, use three or fewer elements per section of a presentation.