Engineering is done with numbers; analysis without numbers is only an opinion.
Akin's rules were written for spacecraft engineers but travel well: any proposal without numbers attached is a preference wearing technical clothing.
In practice
- A proposal claims the migration will "significantly reduce" support load; asked for a figure, nobody has one, and the estimate turns out to be a hope.
- A safety case that says a component is "highly reliable" without a failure rate is a preference in engineering vocabulary.