Non-tech "hard skills" that are easy to evaluate

[marshwiggle]

Whenever a colleague sends me a well-formatted email, or responds to my emails with in-line/matching bulleted lists, I'm so happy to know we're on the same page about communication. When colleagues send four-paragraph missives that convey effectively the same information, but elegantly woven into a composition with introductions, transitions, and elegant prose, I groan and have to fetch my sieve to sift out the elegant cruft and determine what, exactly, I need to respond to or whether they actually did respond to all my question.

Although I'd like to think that I'm not too bad about this, I suspect you might not like receiving e-mails from me.

This illustrates that there's not an unambiguous definition of what constitutes a "good" email, since that will depend on who is evaluating it. So my original idea of "hard" skills, would include the idea of pretty universal agreement on how to evaluate it.
(Again, for a person going to a job interview, they wouldn't need to know who was going to interview them to know how to display the skill.)

[mamselle]

Maybe the deeper skill involved is assessing your audience, and writing to their ear.

M.

[Anselm]

There is the ability to quickly look up accurate information online and also in a library.

[dismalist]

Some of the ideas on this thread look promising, but they would all be illegal if they had disparate impact. :-(