# Re: my lame cladistic questions

```What are (in easy words):
[...]
- the tree length measured in steps?
```

Each change from a state to another is called a step. The total number of those is the length of the tree.

- consistency and retention indexes;

CI = (length of the tree)/(minimum number of steps that any conceivable tree could have).

RI = ((maximum number of steps that any conceivable tree could have) minus (tree length))/((maximum number of steps that any conceivable tree could have) minus (minimum number of steps that any conceivable tree could have)).

`And while we are at it, the rescaled consistency index = RC = CI x RI.`

All of these apply not only to entire trees, but also to individual characters.

- a jackknife frequency;

Jackknifing is a method of determining how robust a tree is. The more often a clade is found in this procedure, the higher its jackknife frequency = jackknife value = jackknife percentage...

- a Bremer support value;

How many more steps are required to destroy that clade. That is, if a tree with one more step lacks the clade in question, that clade had a Bremer value of 1.