Until and unless someone does a rigorous scientific study evaluating different interviewing techniques, preferably using a double-blind randomized trial, there's no point in beating this dead horse further.
There's one big, possibly insurmountable problem in approaching hiring as hard science: In order to test whether a specific approach is objectively more successful at identifying good employees, we'd first need an objective measure of whether someone is a good employee.
Someone is going to bring up metrics here. If you're talking about programmers, then you can grade them based on the number of lines of code they write per week, but that doesn't tell you anything about the quality of the code. You could try to account for that by quantifying the bugginess of the code or measuring the performance of the code. But then, is the code readable? Ok, let's say you quantify that too.
Now how do you want to weigh those metrics against each other? Do you care more about performance or readability? It might depend on the role, the kind of product you're making, or who else might be working on or maintaining the code. It might depend on the boss's personal views.
Ok, so you have all of that to contend with, but then there are all kinds of other considerations. Is the new hire a cultural fit for the company? Is the new hire a good personality match for the boss? Will the candidate work well in the kind of work environment that the company has? Some companies are more relaxed and some are more intense, some slow paced and some fast paced, some appreciate directness and some require political savvy.
Even within a company, it can be hard to identify an employee's value. I remember back years ago, I worked at a helpdesk position and they were trying to implement metrics to measure performance. One guy did great by the metrics they were collecting. He closed tons of tickets and put in his notes and time, but his work was sloppy, his notes were poor, and people didn't like him. Another guy almost got in trouble for not closing enough tickets fast enough, until the manager realized that he was taking the hardest cases, and taking the time to help and train his coworkers. I've seen people who aren't the best performers, but they have a great attitude and help keep morale up.
Honestly, as someone who hires and manages people, I find it impossible to quantify an employee's value or compare their worth in any kind of precise or objective way. If you can't come up with a way to objectively measure an employees value, then you won't be able to come up with a way to objectively measure the methods of predicting their value.