Actually, hiring assessments do exist and are legal to use. Creating hiring assessments is part of the field of Industrial/Organizational Psychology (I believe

Actually, hiring assessments do exist and are legal to use. Creating hiring assessments is part of the field of Industrial/Organizational Psychology (I believe it's called "Work Psychology" in the UK). For example, one I/O Psychologist I know has a consulting business, among other things, administering an assessment called the Totalview 2000 to potential hirees for many organizations. It basically works by first testing the personality and several aptitudes of existing top performers for a specific job at an organization to create a benchmark for top-performers, and then comparing the scores of applicants against the benchmark. Unfortunately, as such it is very specific (e.g.: the benchmarks for the same position at two different offices of the same engineering firm differ slightly because said offices take different clients), and only works well if you already have several identified top performers.