Section 8.3. Types of Questions and Answers


8.3. Types of Questions and Answers

In this section, we present a candidate classification of questions and answers. For both questions and answers, three different types are described: fixed, open, and controlled. Depending on the system needs, various combinations of questions and answers can be used.

8.3.1. Question Types

The two types of questions that are likely to be most familiar are fixed questions and open questions. A fixed question provides a list of preset questions to a user, where the user's choice of question can be taken only "as is" from this list. At the other extreme is an open question, where a user has complete choice and control over the question; guidance as to the question construction may be provided to the user, but the user enters the question in free-form text.

A controlled question lies between the extremes of a fixed question and an open question; it is a question whose content is partially fixed, although modifiable by the user. Two potential variations of a controlled question follow:

  • The fixed question might allow for additional text to be added, forming a modification of the original question. The modified question would be presented subsequently to the individual for authentication. For example, consider the following question that supports customized addition of a name by an individual to the original question. In this case, the individual would choose an appropriate Name along with his answer to the question, and at subsequent authentication, the question would be asked along with the individual-provided name.

     What is Name's middle name? 

  • The fixed question might support a combination with an optional user-provided hint, where the hint would be presented to the individual for authentication. For example, to the following original fixed question the user might provide the following hint: "Dog." The question and the hint would be provided to the user at authentication time. For the user, this hint might indicate a special date associated with his pet dog, such as its date of purchase. In this case, during answer registration, the individual is asked to provide a hint, and during answer presentation, the hint is provided for the user as an aid to recalling his answer.

     Answer Registration  What is a memorable date for you? Date  Hint: Hint    Answer Presentation  What is a memorable date for you? Date  Hint: Dog 

8.3.2. Answer Types

A similar distinction applies for fixed answers, controlled answers, and open answers. A fixed answer set involves user selection of an answer from a preset list of answers. At the other extreme, an open answer involves a user manually entering his response. Guidance may be provided as part of answer registration, but the answer is entered in free-form by the user.

A subtle variation is a controlled answer, where the answer space is neither fixed nor open. Some ways in which this might be achieved are:

  • Providing a fixed set of answers where the answer space is large enough so that most potential answers are allowed. For example, in case an individual answers with a geographic location, the answer may be entered using drop-down menus listing all possible cities, states/provinces, and countries for some region.

  • The individual is able to enter an answer, but the format of the answer is controlledanswers that do not conform are rejected. For example, an individual might be asked to provide a memorable numeric value so that alphabetic and punctuation characters would not be permitted for inclusion in the answer text.



Security and Usability. Designing Secure Systems that People Can Use
Security and Usability: Designing Secure Systems That People Can Use
ISBN: 0596008279
EAN: 2147483647
Year: 2004
Pages: 295

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