The most important thing a manager does

The most important thing a manager ever does is make hiring decisions (in places where they still do that). Nothing else has the same long term impact on an organisation, for good or ill.
So why do we rely on brief samples and instinct? Can we agree that hiring processes are unreliable in determining a good fit for both parties?

The best model I have heard of is a multi-month trial period, with unconditional opt out for either party at the end, and a compensatory payout for the employee, say a month’s pay, paid regardless of whichever party terminated.

It’s the only way to really get to know each other, warts and all.
Paying somebody a month or two’s pay to leave is cheap, compared to having them stay.

If an employer dislikes you so much that they’re prepared to pay out and restart the hiring process, that is painful but not as painful as staying in the job.

I dont know a fairer way to get an optimal outcome. The cost of getting hiring wrong is immense, and no amount of interviews and stupid little tests will fix it.

P.S. another benefit of this approach is that it will encourage employers to make more speculative hires, thereby increasing the diversity and inclusion of the organisation, which enhances creativity and culture.

P.P.S. A corollary is that a referral is more likely to be successful than any recruiting. Pay staff to refer others, then automatically make them the support buddy of that new employee. This creates a visible accountability for their recommendation.