Lists & hierarchies

The lists we've seen so far can be called 'flat' lists, meaning all the items are in the same group and listed at the same level.

Here's another flat list:

We would say the list is "1 level deep". (We don't count the title as a level.)

Here is the same list, but now organised 2 levels deep. What are the two levels?

Do you see how a new type of relationship has been highlighted in this structure?

The list is about improbably named American Civil War generals:

• Level 1: Which side they were on (Confederate vs United States).
  • Level 2: Names of the generals.

This relationship was always there in the list items, but by grouping the items and then labelling those groups, we make the relationships more clear.

Let's go back to our original idea about listing "things in front of me right now".

Here's a new, expanded version of that list:

What other relationships could we find within that group?

What about, "Things I like vs don't like"?

What can you tell from this list?

This list is a survey of how I feel about items around me, and the most obvious conclusion is that I am lucky to be surrounded mostly by things I like.

It also forms a portrait of a specific type of working space which has laptops and monitors mixed up with food, colourful pens, trees outside the window.

Also notice this list has three categories.

It could have as many categories as you want. The categories have varying numbers of items, described in varying levels of detail. All those things can change.

What's really important here is the depth of the categories.

In that regard, this is a 2-level list, with categories then items.

How was that? Pretty easy, right?

Compare your list to other people's, especially if you're all in the same room.

Most likely, there are differences, even if only subtle, in what each person has listed, with what detail they have described each item, and how they have categorised the items.

These differences give you clues about each person's character, point of view, and model of the world.

That's a lot for a simple list!

Let's repeat this activity but increase the complexity by changing the categories we use.