Input-Process-Output-Feedback (IPOF)

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Input-Process-Output-Feedback: Also known as the IPOF, this is the reference transaction that takes places between the patron and the reference librarian. The transaction begins with Input from the patron, generally in the form of a question. Next comes the Process, which involves trying to answer the question, either through research or further clarifying questions. Then comes the Output from the reference librarian, either in the form of an answer or again with further questioning. The patron then gives Feedback. If the inquiry has not been answered then the session begins over starting with Input again.


This approach is generally credited to Robert S. Taylor, who described this type of transaction in his groundbreaking article, “Question-Negotiation and Information Seeking in Libraries.” Taylor (1968, p.79) looked at the question-negotiation process as, “a micro-event in a shifting non-linear adaptive mechanism.” He believed that open-ended questions were a key component in helping the patron.


INPUT – Taylor (1968, p.80) describes the beginning of the transaction as, “one person tries to describe for another person not something he knows, but rather something he does not know.”


According to Taylor the questions can come in four levels:

  1. Unexpected need for information – This has been described by Taylor (1968, p.82) as a, “vague sort of dissatisfaction,” where there is a conscious or even unconscious need for information from a patron.
  2. Formulating the need in ambiguous terms – This is described as a, “conscious mental description of an ill-defined area of indecision.” (Taylor, 1968, p.82)

  3. The formal statement of the need for information – At this level the patron can make a very concrete question about the subject matter and describe their level of doubt.

  4. The question as presented to the reference librarian – At this level the question presented is so specific that the reference librarian must think in terms of what information packets are available (i.e. books, periodicals, maps, etc.)


PROCESS – After the input portion, the reference librarian puts the question through five filters

  1. Determination of subject – This is done by redefining, expanding or narrowing the subject in order to get a better understanding of the question.
  • Objective and motivation – This helps to explain why the inquirer wants the information. Taylor also argues that this is the most critical filter.

  • Personal characteristics of the inquirer – This determines the context of the question.

  • Relationship of inquiry description to file organization – The answers from the inquiry questions help provide clues for formulating a search strategy.

  • Anticipated or acceptable answers – The reference librarian tries to alter the patron’s idea of what the preconceived notions of what they expect their answer to be.


    OUTPUT – After the reference librarian has narrowed down the question, and found some pertinent information he then gives the patron some answers. After the patron is done listening, “he becomes aware of the capabilities of both the library and the librarian … and he is forced in the negotiation process to place limits of time and size on his inquiry.” (Taylor, 1968, p.91)


    Taylor (1968, p.91) also wrote that the urgency of the inquiry was a deciding factor in how the reference librarian would respond. “The inquirer may say ‘I need this in 30 minutes.’ By doing so he has pretty well determined what form he will accept and what questions I can ask.”


    FEEDBACK – This last step in the IPOF is one where the patron and reference librarian are able to decide whether or not the question has been answered. As Taylor (1968, p.99) wrote, “the inquirer’s response in turn guides, alters, or limits future display searches, and answers.” Taylor further goes on to say that alternatives should also be presented to the patron, with very specific instructions as to where these alternatives may lead. The key here is that the patron must be presented with options, “which match his type of anticipated answer.” (Taylor, 1968, p.100)



    Taylor, R. (1968). Question-Negotiation and Information Seeking in Libraries. In B. Katz & A. Tarr (Eds.), Reference and Information Services: A Reader. (1st ed., pp.77-106). Metuchen, N.J. & London: Scarecrow Press, Inc.