Effect

Rank

Criteria

Almost never

1

Failure unlikely. History shows no failure

Remote

2

Rare number of failures likely

Very slight

3

Very few failures likely

Slight

4

Few failures likely

Low

5

Occasional number of failures likely

Medium

6

Medium number of failures likely

Moderately high

7

Moderately high number of failures likely

High

8

High number of failures likely

Very high

9

Very high number of failures likely

Almost certain

10

Failure almost certain