NGO Security has a good explanation of how to create more granularity and levels for risk assessments with a Likert Scale:

You don’t need to be a math or stats-guru to use a Likert Scale, it’s actually quite simple to implement and understand (an especially good feature when explaining the rationale for security decisions to management). For risk assessment, here’s how it works.

For probability, use the following ratings:

1 – Very improbable
2 – Improbable
3 – Somewhat improbable
4 – Neither probable or improbable
5 – Somewhat probable
6 – Probable
7 – Very probable

For impact, use these ratings:

1 – Very insignificant if it happens
2 – Insignificant if it happens
3 – Somewhat insignificant if it happens
4 – Neither significant or insignificant if it happens
5 – Somewhat significant if it happens
6 – Significant if it happens
7 – Very significant if it happens

Take the rating values for a possible incident and multiple them together. For example, let’s say the potential of someone stealing office supplies at a large NGO’s HQ is probable (6) but insignificant (2). That gives the incident a value of 12.

Compare that to the potential of a staff member being abducted in a certain conflict zone. Let’s say it’s somewhat probable (5) and very significant (7) if it happens. This incident tallies up as a 35.

The higher the number, the more time and effort you should devote toward preventative and contingency measures.

That is a lot easier to read, although less entertaining, than the Lickert post at Oregon State University.

A Lickert scale is a multi-item instrument composed of items asking opinions (attitudes) on an agreement-disagreement continuum. The several items have response levels arranged horizontally. The response levels are anchored with sequential integers as well as words that assumes equal intervals. These words–strongly disagree, somewhat disagree, neither agree or disagree, somewhat agree, strongly agree–are symmetrical around a neutral middle point. Likert always measured attitude by agreement or disagreement. Today the methodology is applied to other domains.

[…]

Referring to ANY ordered category item as Likert-type is a misconception. Unless it has response levels arranged horizontally, anchored with consecutive integers, anchored with words that connote even spacing, and are bivalent, the item is only an ordered-category item or sometimes a visual analog scale or a semantic differential scale.

“I can only strongly disagree, somewhat disagree, neither agree or disagree, somewhat agree, or strongly agree with you.”