vii-i8

triplets are then constructed: (~, 0.2,3), ... , (~, 0.2, 12), (~, 0.3, 3),

 .., (q, 0.6, 9), (q, 0.6, 12).  For each search request which is satisfied,

the following data are then obtained:


    1)  M (q, C, n) equal to the minimum number of documents which are
        scahned by the given search scheme in order to "satisfy" the
        request;

    2)  P (q, c, n) equal to the percentage of documents retrieved by the
        given search scheme contained in the first n documents retrieved
        by a full search of the document collection;

    5)  R (~q, c, n) equal to the number of relevant documents contained in
        the set of documents retrieved by the given search scheme over the
        number of relevant documents contained in the first n documents
        retrieved by a full search of the document collection.

        Let ~ = {q1, ~, ... , ~J be defined as the given collection of

        n test queries, and let ~co,no = ~~l' ~          ` ~ no~ be

        defined as the set of all queries such that ~q. £       C ~
                                                    3      co,no
        implies that the request (q.,co,no) is "satisfied"; the data
                                    3
        produced from all request~ which were satisfied is then condensed
        in the following manner:

let             Kco,no

    M (co, no) = i=l

M(qi. Co,No)
   3,

Kco,no

                        Kco,no

           P (co, no) =  j=l

                                   , Co,No)

                                Kco,no

             Kco,no

R (co, no) =  j=l

R(~i~~co~No)


Kco,no