When you create an object variable in one application that refers to an object supplied by another application, Visual Basic must verify that the object exists and that any properties or methods used with the object are specified correctly. This verification process is known as binding. Binding can occur at run time (late binding) or at compile time (early binding). Late bound code is slower than early bound code. To make your code early bound, and therefore more efficient, you must set a reference to the type library that contains the objects you want to refer to, and you must declare your object variables as specific types.