What's the difference between an index and a scale?

Question

I've read Babbie and, while he's usually really good at explaining stuff, this is escaping me.

Answer 1

Index indicate the change / variance against some basic point in %age terms, whereas the scale measures absolute level.

Answer 2

In general, Index usually refers to a system used to make finding information easier.

However, scale could be used as
1) an ordered numerical sequence used for measurement. Example: Please rate your experience on a scale from 1 to 10.

2) Size; scope. Ex. The Holocaust was insanity on an enormous scale.

3) The ratio of depicted distance to actual distance. Ex. This map uses a scale of 1:10.

4) A means of assigning a magnitude. Ex. The magnitude of an earthquake is measured on the open-ended Richter scale.

Hope this helps!