I'm not going to make a judgement call that the manager of the team MUST make. But here's the premises for how to make that sort of decision.
When to Fire
The bottom line is, if after a "reasonable" amount of time, feedback and resources are available to learn, if the person can't come up to speed in the same time frame that most of his collegues can, then he should be fired.
For most jobs, there's a known length of time for a learning curve. In my experience, a year is on the long side - valid in some extremely complex jobs, environments and organizations, but 3-6 months is often the norm for many engineering positions working with standard technology in a standard way with a typical culture.
Another big catch is that many companies may have a probation period - if there's serious issues with a new hire, don't let it lag past the probation period - it's there specifically give you the option to get rid of a bad hiring choice without the tremendous overhead of most corporate hiring processes.
What to Do Before Firing
#1 thing - Give feedback
It is no fun. No one likes to say negative stuff. But the most ethical thing (and often required by HR process) is to alert the employee that there is a problem with performance. It makes sense.
Think of the case in point - without feedback, there are two options to the other guy's side of this story. From his point of view:
Option 1 (no feedback) - I've been working hard for this company, doing my thing, getting it right. They came and asked me to take training on Saturdays and Sundays with Senior Management. They must really think I'm a rockstar. I'll continue to crank away, but these optional meetings don't really fit with my family obligations, so I'm grumpy (or will say no). They really should be more considerate of the needs of top performers.
Option 2 (with feedback) - Eesh, I hadn't realized my job was in jeopardy! I thought I was getting it, but my manager just said that I"m missing major concepts and he gave me 3 examples where I created a pretty big mess. I think this weekend training is the only way to catch up, and I hope I don't act like a jerk with senior management. I'll make the time and be thankful for the extra chance.
The difference here is that the guy is aware that he's messing up.
It's best to give direct guidance on what it will take to correct the situation and how this can be demonstrated and measured. Examples of problems, and what needed to happen better are good. Anything clear and unambiguous. But be careful to say "if you do this, it'll let you keep your job" unless that's true. It's easy to get into that case - for example, being reliably on time to work is a must have in most environments for good job performance. But it's not the ONLY qualification. You have actually do your job as well. Just sitting there, drooling, isn't going to save a job.
In many environments, there's a "probation" cycle of:
- plan of action to improve
- execution of better job performance action plan
- yes/no decision
In a big company, this can be very formalized.
In most hard jobs, there's not a very, very clear plan of action. If you have a wrote procedure, then it's pretty clear - which is why safety violations, for example, can involve immediate firing - they are intentionally clear, unambiguous, and specific.
But in knowledge work "think harder" is not meaningful advice. So a plan of action is often worked out jointly. The manager says "I need more of X or less of Y" and the employee says "I could do that this way or that way, but I need A or B". It can't be ultimately the employee's choice, because there are finite demands. But where it's possible, the process of getting from bad to good is something the employee can and should give input on.
Consequences on Staff
I've been through some pretty bad layoffs, and I can honestly say, I think it's harder on the manager than on the staff. Looking into someone's eye and saying "you're not good enough to work here" - is the worst part.
Staff reactions will vary by person and predicament. But in a rightful hiring, they are usually:
(Most) - phew, the troublemaker is gone, we can get back to work! Most people who like the job and know what good work is (they know, because they do it), will know that this person is not getting the job done. Usually knowing that their bosses won't ask them to pick up the slack and allow the problem to continue is a relief to most. Particularly if they know there was a reasonably fair process.
(Some) - Oh no!! Am I next??? Those that didn't get why this person was a poor perfomer will ask. Often it helps to out line what you expect "if you X, Y and Z in a reasonable time frame, we're good". Stay out of what the problem person did, stick to your own expectations and clarifying if the other employees are meeting them in your opinion. Back to feedback - good or bad, people need it.
(A few) - The totalitarian dictators are opressing us! Yeah. There will be a few who hate that anyone was fired. My experience is that they won't raise it to management, they will raise it with peers. The big question is - OK, if he stayed, someone was going to pick up the slack... given that you wanted him to be employeed here, would you have been willing to do your work and his? This isn't as crazy as it sounds. Once and a great while, the answer is "yes" and some interesting discussions can ensue.
Worse yet, is the opposing issue - collect too many non-performers, and you create a retention issue. If you have a now-experienced person who wanders around clueless on concepts, then when new people come, he will be their impression of a standard employee. That's worse for morale than the momentary pain of firing the real problem.