How do we assure competencies for working across units?
Are there any models out there that really work?

There are two aspects to this question and both are important. First,  the capture of competencies. The competency of an individual is dynamic and ever evolving. To have accurate and up-to-date information on competencies, the mechanism for capturing competency data must match the ever changing nature of competencies. To that end the idea process would allow for anytime updating by the individual as their experience, education and skills evolve. There also needs to be a simple way for managers to validate the accuracy of the information that individuals enter.

The other important aspect to competencies is that the competency information is accessible where it is needed. It is of no value if it is stored away in a file in HR.  There is great value in having competency data available at the point of making staffing decisions. This equips the decision makers with essential information that will assist in assuring that best match possible between a nurse providing care and the patient.

I imagine that there is evidence that having access to the competency information at the point of making a staffing decison has a huge impact on patient safety, and satisfacton levels. 

There are competency decisions to be made when determining which person to assign to a unit and then there are patient care assignment decisions that require one to consider the individual's experience along with the competencies when making the patient care assignment for a shift.  There are many state regulations now that require an RN's experience also be considered when making patient assignments.