Main idea activities' main goal:
A thesis that joins assertion to topic

Most activities for helping students generate ideas for writing are actually aimed at the production of a writing topic rather than a main idea. Activities that do not produce an assertion about a topic cannot be said to produce a main idea.

A main idea, which we call a thesis statement, is always a declarative statement that makes an assertion about a topic.

Incidentally, the concept of a main idea for writing has a parallel in the grammatical concept of complete thought that characterizes a sentence.

Freewriting

Freewriting is typically described as having students write to discover some topic that interests them. Freewriting may help students identify a writing topic; however, it does not necessarily help students select a thesis about that topic.

In fact, freewriting may hamper some students' attempts to find a thesis. It increases the amount of information from which they must select a topic to assert something about.

Brainstorming

Brainstorming was devised as a group activity. Researchers say its best use is as a group activity for seeking a solution to a clearly delineated problem. As a solo activity or as a group activity when no focus is specified, brainstorming has not been shown to be an effective means of generating useful ideas.

Mind maps

Mind maps were designed to be used in study and analysis of existing ideas. They are graphic representations of the ways ideas are associated. Mind maps take main ideas apart and show how the parts are related. They cannot be said to be main idea activities because they do not produce a verbal assertion about the topic of the map.

Tree structures

Tree diagrams resemble a cross between a mind map and an outline. They show divisions of a topic by means of a stylized structure. Instead of producing a main idea, they produce increasingly smaller sub ideas.

All of these methods of generating ideas are limited in their usefulness as main idea activities. They are much more effective when used to develop support for main ideas.

I suggest students use the thesis builder strategy to create a main idea and activities such as mind maps or brainstorming to develop the points of the writing skeleton™.