[michaelt]

  there is a HUGE body of research to show that the 
  single best hiring process you can use for hiring 
  a worker

The best process, assuming you have to use a single process for every job in the world? Or the best process even when hiring for a specific role?

I can understand IQ being the best choice if you had to judge poets, plumbers, town planners, golf instructors, programmers, salespeople and warehouse workers using the same process. But surely if you're exclusively hiring for one of those roles, you'd want to test their domain-specific knowledge?

[lmz]

As was written above:

> Work-sample tests are also very good for hiring for specific jobs, and are grossly underused in hiring in the United States.

[michaelt]

But isn't essentially all hiring for a specific job?

[tokenadult]

Industrial and organizational psychologists have researched this issue, with hundreds of studies spanning most different kinds of jobs in most developed countries now published. A work-sample test is especially strong for spotting people who need to do something right away after they are hired. For any worker who may need to learn new things on the job--and that is a lot of different kinds of workers, in a lot of different industries, and almost all managers--a "general mental ability" test adds to the predictive validity of selection applicants who will do well on the job over time as industry conditions and market pressures and technologies change.

[divegeek]

Not necessarily. For example militiaries routinely recruit (hire) first, and then later figure out where to put the hiree. The same is less common but does happen in industry as well with entry-level college graduate positions, and in some cases even with higher-level positions.

Even if what you say is true, though, some companies intentionally hire people without the necessary skills to do a job, then train them. In that case there's no point in testing them for job-specific skills they don't have so what you want is a way to determine which candidates are likely to be successful after training.