Ideas belong together if they share a common property. But, as you saw in deduction and induction, ideas are always written in sentences that have a subject/predicate structure. Thus, the common property linking a grouping of ideas will usually show up because the sentences all:

Discuss the same kind of subject

Express the same kind of predicate (action or object)

Imply the same kind of judgment.

Here "same kind of" does not mean exactly the same. It means falling into the same category or able to be described by the same plural noun.

If the subjects are all exactly the same, you look for a similarity by which to group among the predicates. If the actions or objects are all exactly the same, you look for a similarity by which to group among the subjects. If neither the subjects nor the predicates are the same, you look for similarity in the judgment implied by the statement.

Identifying the actual similarity is harder than it sounds, particularly if the points are nicely phrased, because the language blocks your critical thinking. We all know about, and have been soothed by, the Five Forces, the Seven Ss, the Four Ps, the Seven Habits, etc. The trick is to get behind the language to see the bare structure of what is being said.

Here, for example, is the sort of thing one reads all the time:

There are four characteristics of the new Planning and Control system:

1. The planning cycle and its attendant control mechanism should be on an annual basis

2. The plans should be built up via an integrated system

3. The plans should be compiled in the context of a strong directional lead from the top of the division

4. The planning system will distinguish between the current practice and the planned change

On first reading, this set of points sounds plausible. The language used is rather elegant, which tends to make one think the author is communicating something useful. But there is still that intellectually blank assertion at the top.

If we try to get behind the language to see what the list actually communicates, we see first that the subjects of the sentences are all the same-plans or the planning system. The connection between the ideas, then, must lie in the predicates, which say that the planning system is

-Annual

-Integrated

-Top down

- Distinguishes between present/future

Now; stripped of its style, you can see that the grouping does not really support a message. You ask yourself, What's significant about a planning system that possesses these four characteristics? The fact that the points are true is not sufficient to make them relevant, and the blank assertion prevents us from thinking further about them.

This impetus to think further is, as I said at the beginning, the major reason for drawing inferences in the first place. A grouping of ideas like the planning and control system characteristics listed above does not push your thinking upward to express a summary insight, and therefore cannot guide it forward to develop new thinking on this particular subject. Actually, after a good deal of rewriting, it turned out that what the author meant to say was:

The objective of the new planning and control system is to focus each unit of the organization on improving profits, by

- Requiring annual profit plans from each unit

- Coordinating their contents at each reporting level

- Controlling managers specifically against them

Bear in mind that if, as in this case, you do not find a clear relationship between the ideas you have grouped together as “problems" or "reasons" or "conclusions," etc., that is always an indication that there is something wrong with the ideas in your grouping, and that further thinking is therefore required.

The planning and control list contained only four points, and thus was relatively easy to sort out. Most lists produced tend to be longer. In that case, having isolated where the similarity in your grouping of sentences lies, the next step is to look for closer links between the similarities.