Specific Purpose and Central Idea

  • The specific purpose is a brief phrase stating your goal for your speech.
  • The central idea is a brief one-sentence preview of the main points in your speech.

Rules for the Specific Purpose

  1. The specific purpose should begin with the infinitive PHRASE “To inform my audience. . .”
  2. The specific purpose should include a number of aspects, reasons, steps, parts, etc. (between two and five). This will be the number of main points in your speech.
  3. The specific purpose should state the topic of your speech.
  4. The specific purpose should include only one main idea for your speech.

Incorrect / Correct
To tell about baseball. / To inform my audience of the four (4) main skills in baseball.
To inform my audience about making dolls. / To inform my audience of the five (5) steps in making dolls.
To inform my audience about someone’s life. / To inform my audience about three (3) stages in the life of Tupac.
You should eat organic food. / To persuade my audience to eat organic food for two (2) reasons. OR: To persuade my audience to eat organic food by showing how it satisfies their needs.

Rules for a Central Idea

1. The central idea is always written as a complete sentence.

2. The central idea should include the number from your specific purpose.

3. The central idea should list out the 2-5 specific main points you will address in your speech.

4. The central idea should match the specific purpose (both the number and the topic). Compare the correct specific purposes (above) and the correct central ideas (below) to see how they match each other.

Incorrect / Correct
There are four (4) main skills in baseball. / The four (4) main skills in baseball are batting, catching, pitching, and running.
A doll makes a great gift. / The five (5) steps in making dolls are buying the bisque parts, designing the body, buying body fabric, painting the bisque parts, and sewing the body.
Tupac made many contributions during his life. / The three (3) important stages in the life of Tupac Shakur are his childhood, his education, and his career.
Organic food is the best and so you should eat it. / Two (2) reasons you should eat organic food are its lack of chemicals and its lack of polluting the environment. OR: Organic food can satisfy your need for healthy food and a safe environment.

Rules for Main Points

  1. Your main points should come directly from the central idea.
  2. The Main Points of Main Ideas for your speech should be natural divisions, reasons, or steps to support your central idea.
  3. If your specific purpose states that you will show three steps, and your central idea lists three steps, you will have three main points. Each main point will be a step.
  4. You should always include at least two (2) main points, but no more than five (5) points in your speech.

Example:

Topic: Glassblowing.

General Purpose: To inform

Specific Purpose: To inform my audience of the three steps in blowing a glass bubble.

Central Idea: The three steps in blowing a glass bubble are 1) gathering glass on the rod, 2) reheating the glass gather in the “glory hole”, and 3) puffing small amounts of air into the rod.

Main Points:

1. The first step in blowing a hot glass bubble is to gather molten glass on the end of the hollow rod.

2. The second step is to reheat the blob of gathered glass by inserting it into the glory hole.

3. The third step is to puff small amounts of air into the hollow rod until the hot glass begins to inflate.

Specific Purpose and Central Idea Exercise

For each speech assignment you will be asked to choose a topic and write a specific purpose (SP) and central idea (CI) at the top of your outline. For this assignment, please choose three (3) topics for three different informative speeches. Write a specific purpose and central idea for each informative speech topic in the space below. (These topics are just possibilities; you will not be required to give speeches on the topics.)

Topic:

General Purpose: To inform (about a process )

Specific Purpose:

Central Idea:

Topic:

General Purpose: To inform (about an object/person )

Specific Purpose:

Central Idea:

Topic:

General Purpose: To inform (about an event or concept )

Specific Purpose:

Central Idea:

Source: Adapted from Dwyer, K. (2002). Public Speaking Workbook, 7th Edition. Boston: McGraw-Hill Primis Custom.

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