Output value is a step in which one or values captured at a 
specific point in your test or component and stored for 
duration of the run session. These values can be used later 
in the different point in application.

In generally, output of application shows different values 
and it is not based on action in the current page/action in 
the application then the word output value is coming in 
QTP. And it has four types, these are given below.(These 
are usage in application at different places/purposes)

standard o/p value: In web aplication, link page shows 
differently based on the user actions in the previous page.

Text o/p value: Text ouput value may behave differntly 
based on using the diferent environments in window based 
application. It is recommanded to retrieve the text from 
the application window by using standard output value to 
the value of object text property.

Database o/p value: database output value to the output the 
value of contents of database cells based on the result of 
the query that you define on a database.

xml o/p value: xml output values to output the values of 
xml elements and attributes of xml documents can be used.