One of the reasons I strongly advocate for “promoting from within” is that many recruitments fail. Real life is not Star Trek, your company is not a Borg collective where resistance is futile and assimilation is inevitable. What looks like a great “fit” during the interview process can turn into a terminal mismatch for many, many reasons that are beyond your control.
We once had an inside salesman quit in the middle of his morning commute before his first day on the job; he pulled off I-95, found a pay phone (which tells you how long ago this was), and quit before he even started. That commute was just going to be too much for him and his wife was not going to move because their kids loved their teachers.
Other failures were the result of a mismatch between the actual job duties and what the candidate expected to be doing. Having “manager” in your job title does not exempt you from being an individual contributor or from doing your own photocopying and filing. These things may seem trivial in the grand scheme of things but we live in the day-to-day, not some grand scheme.
Few things in life are scarier than starting a new job and almost immediately realizing that it is not a good fit. This is particularly true if relocation was involved and head hunter fees have been paid. With the advent of two career couples, the problem might not even be with the person you hired. If the spouse is unhappy, the stress can make fitting in impossible. Absent those external issues, new hires can be resisted by the rest of the team out of jealousy or temperament. I have blogged about the differing terminology and technology around our industry; a new manager may speak a different “gear dialect.” A passed over in-house candidate may actively undermine their authority. These changes in “operating system” can expose deficiencies in training; a great designer may be lost without a full software suite. Your team may not feel comfortable with changes in their routine either.
People are way more complicated than light bulbs. You cannot plug new ones in without tripping a few breakers. We engineers tend to concentrate on the hard sciences and forget the soft ones like sociology and psychology. That is a risky policy when people are involved. We are not in a position to broaden the mission of Gear Technology into those “squishy” topics but it would be silly to pretend they are not of equal importance to the success of our readers.