I have been involved in employee education/staff development/organizational development for quite a long time.
I have had some experience with the development & implementation of pre-employment 'temperament' as well as competency assessments in several organizations. None of the temperament assessments involved RNs - but I was very impressed with the outcomes of a process for selection of CNA staff. We decreased job turnover by 50% as a result of using the tool to improve our hiring process. The tool was developed by an O/I psychologist -6 month process with extensive testing & validation prior to implementation.
Despite a significant amount of O/I education in my doctoral program, I am still not a fan of pre-employment assessment in general, especially those focusing on temperament. I am not knocking the high-end assessments (e.g., Birkman) that are commonly used to select executives. They are very accurate & valuable, but also waaaay too expensive for general hiring or jobs that are not associated with multiples of 6 figure salaries. Simple (one dimensional) assessments are not valuable. For instance, it is pretty well known that everyone lies on "honesty" assessments.
In my experience, pre-assessment tools are not customized sufficiently to actually reflect the unit/department in which they are used. Instead, they are based upon someone's perception of the 'ideal' candidate - which is usually based upon a synthetic marketing prototype rather than reality. Ex: the 'desired' candidate may be highly empathetic, but the 'real' environment, is much too harsh to support highly empathetic people. My other beef - they consist of 'forced selection' responses (multiple choice, matching, TF, etc) that are more sensitive to the participant's testing skills than their underlying knowledge.
I do support intensive training of hiring managers so that they actually know how to interview and hire!!!! This is a much better solution than trying to use assessment tools to compensate for manager skill deficits. I also support the use of (reliable and valid) post-hire assessments in order to determine what training/development should be included in orientation. The best nursing assessment instrument that I have found is PBDS because it integrates many important dimensions and rated using a qualitative analysis that takes into account the individual's education and experience.