Technical Report - International Military Testing Association

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the average percent time spent by all mcrmbers of, the group, both performers
and nonperformers of the task. The cumulative sum of the average percent
tfne spent by all mmbera of the group is also shown so that for any group,
tasks that consume 50 percent, 75 percent, or any other percentage of total
tima can readily be identified. Tasks arc printed out in descending order
of time spent on them.
. Identiffcatlon of Job Types
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Perhaps the most important statistfcal breakthrough, however, is the
application, by Bottenberg and ChcLstal,of a hierarchical grouping computer
progrsm,developed by Ward, to occupational data. This progrsm, which represents
a major advancement in the state-of-the-art, groups together incumbents
who perform essentially the same work activities regardless of
skill level, grade, experfence, or assignment. In any career ladder there
are many jobs which for all practical purposes are identfcal. The individuals
who do these identical jobs are oaid to belong to the sane job type.
In the grouping program,the ccmputer locates frm among perhsps 2,000 incumbents
who have completed a job inventory for a particular career ladder,
the two individuals vho have the most similar jobs. The computer does this
by comparing every possible pair of fncumbents,ln the sample. A single job
description for this pair is developed with accounts for their work tfmc
with the least error. The ccxsputer then tests all possibilities of combining
a job description of a third irdividual with the first accepted pair,
or forms a new pair. This process is continued until finally the computer
forss a group consisting of o,l members of the sample and reports the error.
The iterative process may be terminated at any stage in the grouping
program. The stopping point la a matter of jgldgfng when the error term
resulting from merging somewhat dissinflar groups becomes unacceptably large,
In a study involving 836 cases in the Personnel Career Ladder in vhich 35
job types were identifled,the grouping process #as stopped at the 118 group
stage. At this stage there were 27 groups containing five or more members.
One of these groups which was composed of ttu, groups identified earlier in
the program was listed as two separate job types and seven other job types
were generated at later stages in the grouping process.
In some job types work is concentrated upon a few tasks while the work
of other job types is quite diverse. In general, it is found that the number
of tasks performed is directly rclsted to skill level--the higher the level
the more tasks are done. Certain supervisory job types can readily be differentiated
fras technical job types, both in terms of specific tasks performed
and in terms of skill lc*Jels of members forming the groups, Other
job types cut across skill levels.
Purposes of Job Analysis
The Af.r Force method of job analysis has been designed, not for a
speciffc purpose, but rather as R general procedure the results of which
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