Master specifications will provide the detailed information, the "I" in building information modelling.
They will describe in detail the same objects that are visually represented in the CAD model. So within the CAD model you will be able to see how many windows you have, where they are located and what they look like. In the specification model the information behind the window will be recorded, what regulations/standards the window must comply with, what workmanship/execution tasks are required, what manufacturer products make up the window and, finally, what regular maintenance is required through the window's life.
It is key that master specification systems raise their game and invest in improving their data and their software so that the full benefits of BIM can be achieved.
It is key that master specification systems and CAD systems interoperate so that this information can be shared and used to its best effect.
What is the alternative? That all of this information goes into the CAD objects and that each practice maintains their own libraries? Over 200 key reference documents change each month. Who will research and maintain these CAD libraries to ensure best practice?
This is why BIM is revitalising master specification systems. It is now the job of master specification systems world-wide to enhance their data and their software to allow their users to make the most of BIM.