Critical Reasoning: The IFPUG definition states "…from outside the application boundary." Since the IFPUG definition reads "…the processed data maintains one or more ILF's, then it is clear that the information must come from outside to inside the boundary. This is important for a variety of reasons. It is clear from the improved definition, calculated values that are stored are data elements for the external input, but calculated values that are not stored are not data elements for the external input. This is true because the calculated value that is not stored has not crossed the boundary (outside to inside) and it is not maintaining an ILF.

In a GUI or OO environment it is common for information to move from one window to the next. The actual movement of data is not considered an external input because it has not crossed the application boundary (outside to inside) and does not maintain an ILF.

The IFPUG Definition does not explicitly state the information must be sent outside the application boundary (like an EO), regardless the information must be sent outside the boundary. This is important for OO because objects communicate with each other. Only when an object actually sends something outside the boundary should it be considered an external inquiry.

Additionally, the IFPUG Manual does not make a clear distinction between an EO and an EQ. It is common in the GUI and OO environments for an EO to have an input side. The only distinguishing factor is that an EQ can not have derived data. If this is the case, then an EO must have derived data (otherwise it is an EQ).