>>> Properly validated psychometric tests are valid predictors of job performance
Here I have a problem - which job performance? Different jobs are obviously demanding different qualities - highly creative but impatient person may be an asset in job requiring instant creativity but a liability in a job requiring steady repetitive tasks and constant attention. So the test has to be matched to a position. But in the original article not only HR gave the same test to everybody, people who decide on positions don't even seem to have information or input on any correlation between position and test results. Given this, I highly doubt such application of testing can have any meaningful correlation with job performance.
Job performance can be defined many different ways, and the most common in field studies is what is most common in the workplace: supervisory, and possibly peer, evaluations. It's not the perfect criteria, but the "perfect criteria" for many jobs exists only in the theoretical. When appropriate, "work performance" is also defined as sales numbers, widgets produced, time-to-complete, etc. It just depends on the study.
> So the test has to be matched to a position.
In many cases you're right (e.g., work samples), but not always. g-centric tests have demonstrated high validity across jobs and contexts. Tests for cultural fit (in which the desired outcome is typically workplace satisfaction and tenure) are typically validated across a wide range of jobs, and so they are applied across those jobs. Things like integrity tests and personality tests can have meaningful validity across jobs, even without seemingly job-relevant content.
Here I have a problem - which job performance? Different jobs are obviously demanding different qualities - highly creative but impatient person may be an asset in job requiring instant creativity but a liability in a job requiring steady repetitive tasks and constant attention. So the test has to be matched to a position. But in the original article not only HR gave the same test to everybody, people who decide on positions don't even seem to have information or input on any correlation between position and test results. Given this, I highly doubt such application of testing can have any meaningful correlation with job performance.