Nothing unnerves a user more than an irrational machine. Every instance of inconsistency by the system will occasion the user to ask, “Why is the system behaving like this? Did I miss something or is the system just badly designed?” Obviously, such questioning can only hurt the user’s confidence in the system’s ability to help them solve their problem.

In Language: Be consistent in how you refer to objects, properties and actions across prompts and menus. Don’t use “ticket” in one prompt and “case” in another; “incorrect” in one and “invalid” in another; “log in” in one and “sign on” in another.

In Voice: Avoid mixing DTMF with recordings; and avoid using more than one voice in your VUI.

In modality: If the user can speak their answer in one menu, don’t take that ability away from them in another menu, unless you explain to them why you are taking it away from them.

Across menus: If you let the user request “repeat” in one menu, don’t take that ability away from them in another menu.

Across contexts: If users are responding to an infomercial and the infomercial tells the viewers that by calling the line they will get to a sales agent, then make sure that the IVR does not offer options that have nothing to do with sales: e.g., offering them to be connected to the help desk or to billing.

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IVRs don’t need to be the bane of call center callers if designed with the principles outlined: be respectful, be intelligent, and be consistent. Have the IVR treat the caller with respect, give the system the intelligence and information it needs to treat each caller as an individual with specific needs, and ensure that the system’s behavior is consistent, rational, and predictable, and you will see the abiding hatred callers seemingly have for IVRs evaporate.