There's nothing like a trial period to see the ability of an applicant. One shift shows you a lot, and a week gives a wealth of information.
But there are times when quick decisions are needed. Do I want this person for a second interview? Does this other person have the minimum competence and ability you need?
Competence is made up of Skills, Knowledge and Behaviour across 10 key areas. Dividing it up this way makes it easier to understand, and can be the basis for job interview questions, a performance review, even a discipline interview.
This example shows how the 3 parts fit together:
Let's say I claim to be a competent driver. If I have the Skills & Knowledge, but not the right Behaviour, you can imagine an inconsiderate road-rager, or someone who never gives way to others.
If I have the Knowledge & Behaviour but not the Skills, it's likely that I can't do a reverse-park or use manual (stick) shift.
Finally, if I have the Skills & Behaviour but not the Knowledge. I probably don't know the road rules, how to read a map or what common road signs mean.
The three together make me a competent driver.
Now check a Barista you're recruiting (as an example):
Skills: speed, familiarity with a coffee machine, physical strength and the ability to multi-task. While making 4 lattes, they are checking the next order in the queue.
Knowledge: they know all about the beans, the different coffees they produce and how the machinery works. Americano, macchiato or skinny latte? Where does Kenyan coffee actually come from? What are the food-safety dangers with warm milk?
Behaviour: a team player who keeps a smile on her face while pumping out product and helping others. Grace under pressure. Always ready to upsell from regular to large size, and fanatical about cleaning.
Apply this to a Chef, Waiter, Dishwasher, Supervisor or Manager. There are different skill sets for every job, but they will always fall under the three headings.
Like the driver, when staff are only strong in 1 or 2 of the 3 parts, problems will arise. How many times have you employed someone to cook who had the Skills but not the Behaviour? Or took on someone warm and friendly (Behaviour) to work as a waiter, but they lacked speed and accuracy (Skill) to do the job needed.