do u know mandatory and assesstive properties. when qtp is 
unable to recognize an object by using above properties we 
will enable smartidentification.by using this qtp 
definitely identifies the object.

QTP identifies the objects in the application with some of
mandatory properties and assistive properties. If the object
changes with these properties, then QTP fails to recognize
the object in the application.

If any such object exists, then we can make enable the Smart
Identification to that object class.

If Smart Identification is enabled for the object class,
then QTP ignores the learned descriptions from the
application, and uses the mandatory and assistive properties
configured to that object class. It learns all the
properties configured in mandatory and assisitive properties.

Smart Identification : Its a mechanism provided by Quick 
Test to identify dynamic bjects whose properties are 
changing time to time....( Say a Submit button changes to 
Save after clicking once)
Now the test property of that button is changed.If we 
generate the script statement 
Window("windowname").dialog("dialogname").winbutton
("submit").click

beacuse submit button is no more available in window

Generally Object Identification is done using the physical 
description (Mandatory and Assistive properties) of that 
object in the object repository.

But If we want to enable Smart Identification we have 2 
ways.

1) enable Smart Identification for Object class
2) enable Smart Identification for a single Object

If we want to enable Smart Identification for entire object 
class

Go to Object Identification---> select the environment---> 
select the object class---> check the enable smart 
identification checkbox in object Identification dialog

If we want to enable Smart Identification for a specific 
object 

Go to Object Repository---> select the environment---> 
select the object class--->select the object---> check the 
enable smart identification checkbox in object Repository 
dialog

And we should select the Base Filter and Optional filter 
properties for the selected object class/object.

When we enable this smart Identification Quick Test will 
try to locate the object based on these properties only.