It’s an interesting concept. Your process seems to shift the bias within your company from “we have made the decision to hire this person, and have 90 days to decide we were wrong. If we don’t decide to admit we were wrong, we’ll keep them,” to a more stringent “we have not made the decision to hire this person, and have 90 days to collect evidence that we should. If we can’t collect that evidence, we’ll let them go.” I wonder to what degree hiring managers and peers in the former mindset feel more invested in making sure the new hire succeeds in their role, and to what extent that will impact performance and outcome of hiring decisions for you.
It also occurs to me that instead of just a few hours, your team now has 90 full days during which to succumb to biases and/or form unhelpful opinions, and if I’ve learned anything about human interaction it’s that even in the presence of evidence (i.e. the work) people’s opinions of a co-worker are largely ruled by how much they “like” them, which is directly related to how much they “fit in.” These opinions feed on each other over time as well, growing towards a stronger consensus over time that tends to rely less and less on evidence (i.e. the work) to self-perpetuate. In other words, once Sally decides that Timmy is a bozo, she is less receptive to evidence that may suggest he’s actually not. And if she shares her views with Jenny, who agrees with her, that feedback loop further strengthens that perception.
Ultimately I suspect it’ll boil down to implementation and how effectively the team can use this process (vs. any other) to drive a good decision. The whole end-to-end hiring/job hunting process is such an unnatural beast that I suspect the intentionality of even the most stringent process like a meticulously applied topgrading interview only amounts to some incremental advantage vs. throwing darts, so I say if you find something that seems to be working for you, double down.
It’s an interesting idea, and I’ll be interested in finding out how this plays out over time — best of luck!