MAS.632 Conversational Computer Systems - MIT OpenCourseWare

ABC D1EF
PRS TUV I WXY
Figure 6.3. The labels on a telephone keypad.
Ilerodive Yoie Reupon .
database to database. But even explicit spelling can encounter collisions
between choices. Although the login IDs mentioned above may be unique on a
particular computer system, for other kinds of databases uniqueness is less
likely. There may be many "Smiths" in a large company, and there are quite a
few "Cambridge" streets in the Greater Boston area, for example. Whenever this
occurs, an alternative selection will have to be provided regardless of the data
input method.
Implicit spelling may be very effective. For many databases, confusability due
to letter-to-key mapping is less significant than collisions due to duplicated
spellings. For example, Davis [Davis 1991] reported on two databases of names of
job applicants and students at a university. In one list of approximately 9,000
individuals, 40% of them shared a last name with at least one other individual,
but only 8% of all names collided with another name using implicit spelling. A
second list of 25,000 individuals exhibited 38% shared names with 21% of the
names colliding.
Choices Touch tone spelling
Brown 27696
Davis 32847
Green 47336
Jones 56637
Smith 76484
South 76884
Figure 6.4. A menu of last names and the associated touch tone spelling.
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