What is a Competency?
Competency models refer to collections of knowledge, skills, abilities, and other characteristics ( ISDTP™) that are needed for effective performance in the jobs.

FIRST,competency modeling is an important innovation in that it is a way to get organizations to pay attention to job-related information and employee skills in the management of employees. In fact, a key difference between job analysis and competency modeling may be that executives pay more attention to competency modeling. In that sense, competency modeling is a way to get job analysis into the mainstream of employee management decisions. Competency modeling could be considered the “Trojan Horse” for job analysis.

SECOND, they are often intended to distinguish top performers from average performers

THIRD, they often include descriptions of how the competencies change or progress with employee level.
 
FOURTH, the ISDTP™ are usually linked to the business objectives and Strategies That is, the ISDTP™ are described in a manner that highlights their relationships to the work or the objectives, or sometimes the ISDTP™ needed to achieve each objective are identified and grouped together. In addition, they are usually defined in terms of observable job behavior

FIFTH, they are developed top down rather than bottom up like job analysis. They not only start with gathering information from executives rather than lower level job employees like job analysis, but they usually start with defining the competencies for executive jobs and then work their way down.

SIXTH, competency models may consider future job requirements either directly or indirectly

SEVENTH, competency models are usually presented in a manner that facilitates ease of use

EIGHTH, typically, a finite number of competencies are identified, and applied across multiple functions or job families. Bounding the competency model in this way simplifies the human resource (HR) systems and facilitates comparisons across functions that support parity in systems like compensation and ease job movement across functions by illuminating similarities.

NINTH, and perhaps most importantly, competency models are used actively to align the HR systems

A TENTH, difference is that competency modeling is often more of an organizational development intervention that seeks broad organizational change (such as HR alignment) as opposed to a simple data collection effort. Characterizing competency modeling as OD incorporates how the competency modeling project is conducted