In trying to categorize integrity in voting systems, its become clear to me that a parallel exists between many other human-technology interactions. Consider the things that have to go right when you want to call someone on the phone:

Dialed as Intended - Given a phone number, you can figure out how to press the buttons to dial it.

Signaled as Dialed - The telephone unit must emit DTMF tones (or pulses) consistent with the buttons you pressed.

Routed as Signaled - The telephone network must correctly route your call based on the signal it received.

Putting it together your call is Routed as Intended.

Obviously the integrity chain is easy for the caller to validate, when the correct person picks up the phone at the other end. But what about when its not? I often phone my sister in the arctic and have to try several times to get through. I could’ve accidentally dialed the wrong number (i.e. not dialed as intended). I could’ve pressed the button quickly and the DTMF tone was not registered (i.e. not signaled as dialed). Or, as often appears to usually be the case, the call is not routed as signaled. The call, being routed through satellite, is often subject to reliability issues, and even bad weather (it IS the arctic!).

Obviously telephone integrity is not currently the focus of much research. But taking these ideas and applying them to electronic voting is.