File pofi-guidelines.doc   Version 1.0   6/19/92


         Guidelines for the Principles of Interpretation


   The principles of interpretation as stated allow some leeway for
annotators and adjudicators to use their own best judgement in
formulating interpretations of questions.  For example, there is
a general rule that context may make one interpretation of an ambiguous
query unreasonable, and therefore ignorable; but deciding in particular
cases that context makes an interpretation unreasonable is largely
left up to human judgement.  This document contains individual cases
that exemplify judgements made by annotators and adjudicators,
along with some general rules-of-thumb, to serve as guidelines
for system builders who want to build the same kind of judgement
into their systems.  When possible, cases will be keyed to the principle
that seems most relevant; at the bottom of this document, the
section "Miscellaneous Cases" contains some isolated cases that
haven't yet yielded a general rule-of-thumb.


1.1.  Only reasonable interpretations will be used.

      Guideline: if there are several possible interpretations of an
   utterance, and the subject should have known that one of them
   would produce a null answer, that one is probably unreasonable.

      More generally, if one interpretation violates a pragmatic principle
   or maxim, such as "Be relevant", and another interpretation is available
   that has no such violations, then the first is probably unreasonable and
   may therefore be ignored.

   Case #1: (hypothetical)

       A1: [a list of flights]
       Q2: "Which ones serve breakfast?"
       A2: [none of them]
       Q3: "Which ones have stops?"

      "Ones" in Q3 is basically ambiguous between referring to a.) the list
   of flights in A1; and b.) the subset of them that serve breakfast.  If there
   had been some flights which served breakfast, both interpretations would
   have been reasonable; but because the b.) interpretation would yield a
   null answer, and the speaker must have known this, it was rejected as
   unreasonable.



2.2.5  References to legs for connecting flights are basically
       ambiguous between referring to the leg or to the entire flight.

      Guideline: references to second or later legs of a flight are
   almost certainly not reasonably interpreted as referring to the
   entire flight.

      Because some annotators believe that a case might conceivably
   arise in which reference to a second leg would reasonably be
   interpreted as referring to the whole flight, this rule has not
   been made absolute.  In fact, no such case has yet (5/15/92) occurred
   in real data.  Here is their hypothetical example of such a case,
   in which Q4 might be taken as referring to the whole flight:

      Q1: "Show me flights from Boston to San Francisco."
      A1: [a table of flights]
      Q2: "What United Airlines flights leave in the afternoon?"
      A2: 
           FLIGHT ID DAYS       FROM TO  LEAVE ARRIVE AIRLINE + FLIGHT #
           --------- ---------- ---- --- ----- ------ --------------------
           106376    DAILY      BOS  SFO  1745   2127 UA93
           393553    DAILY      BOS  OAK  1720   2205 UA281/UA673
           420911    DAILY      BOS  SFO  1720   2214 UA281/UA297

      Q3: "What is the fare for the flight leaving at 5:20?"
      Q4: "What is the fare for United Airlines, flight 297?"


2.11.1  Queries that are literally yes-or-no questions are considered
      to be ambiguous between interpretation as a yes-or-no question
      and interpretation as the corresponding wh-question.

      Guideline: if it seems clear that the subject was requesting
   information FROM the database, and not information about the
   system's ABILITY to provide that information, then a yes/no
   interpretation is unreasonable.

      Some hypothetical cases where the yes-or-no interpretation is
   unreasonable are:

      "Can you show me the morning flights?"
      "Can you tell me if there are morning flights?"


     

                    MISCELLANEOUS CASES


     1. The expression "... flight 915 ..." can't reasonably be interpreted
   as the flight that leaves or arrives at 9:15, as in utterance qx0061ss:

      A5: 
          FARE   ONE  ROUND
        RESTRICT WAY  TRIP   FROM TO  LEAVE ARRIVE AIRLINE + FLIGHT # 
          ---    ----  ----  ---- --- ----- ------ --------------------
           F     $428  $856   ATL BWI  9:15  10:55 EA202
           Y     $286  $572   ATL BWI  9:15  10:55 EA202
           F     $428  $856   ATL BWI 10:02  11:45 DL1204
           Y     $286  $572   ATL BWI 10:02  11:45 DL1204
           .       .     .     .   .    .      .     .
           .       .     .     .   .    .      .     .
           .       .     .     .   .    .      .     .

      Q6: "List the fares for Eastern's flight nine fifteen."