It's not easy to learn a new language. We are all used to speaking in a vague verbal language when expressing degrees of belief. In daily life, this language serves us quite well and the damage caused by its ambiguity is minor, but for important decisions it is helpful to use numbers to express degrees of belief. It may be more difficult to elicit numbers, but it is much more efficient. We understand each other better, numerical expressions are more sensitive to small differences in our feelings, and in the end, our decision processes will be better.

From "An Elementary Approach to Thinking Under Uncertainty," by Ruth Beyth-Marom, Shlomith Dekel, Ruth Gombo, & Moshe Shaked.