I__. - International Military Testing Association

For the weapon system design TDS application, our objective is to replace the separate
training time equations for each task module with a single equation that can be applied to
any task. In the desired equation, task modules are described by scores on scales which
reflect various skill and knowledge requirements. The first step in developing such a training
time model is to generalize the task-specific training time model of equation 1 to cover many
tasks. This can be done by introducing dummy-coded task identification variables:
P = sum(i= 1,t) [ a,,h,,xi + acuhclki + a,&,> + amdhmrki +
where xi dummy-coded task identification variable for task i,
i= l...r, and
xi = 1 if the current observation is for task i, 0 otherwise.
[Equation 21
Equation 2 may be thought of a model whose variables are interactions of tasks and
training hours. This model contains 8 times t (number of task modules) interaction predictor
variables. Consider a model in which tasks (e.g., the task indicator variables x are replaced
with task descriptions in the form of scores for tasks on skill and knowledge scales:
P = sumtj = l,r) [ aclh,Jj + acuhZYj + amrhmryj + amrlhmr% +
where yj = score for current task on rating scale j, j = l...r.
[Equation 31
Equation 3 may be thought of as a special case of equation 2, in which the task by
training hour interaction is restricted to that portion attributable to the task rating scale
scores. If the scores measure the task features that drive their training time models, then
equation 3 will account for most of the proficiency variation that equation 2 can account for.
The next step in building our training time model was to identify a set of standardized
skill and knowledge scales. For this purpose, we adopted a set of 26 skill and knowledge
dimensions that was developed by occupational analysts at the USAF Occupational
Measurement Center for classifying tasks in various occupations (Bell & Thomasson, 1984).
More recently, these task dimensions have been revised by researchers for use in assessing
skill transferability between occupations (Lance, Kavanagh, & Gould, 1989).
We obtained ratings on each of the 26 scales (see Figure 2) for all task modules in the
Aircraft Environmental Systems Maintenance (Air Force Specialty 423Xl),occupation. This
occupation contains 57 task modules, each composed of one or more occupational survey
tasks (Perrin, Knight, Mitchell, Vaughan, & Yadrick, 1988). The ratings were obtained
specifically for this R&D work from five Air Force Non-commissioned Officers (NCOs) who
were experienced in the Aircraft Environmental Systems Maintenance occupation.
Agreement among the five raters was measured for each scale by the intraclass correiation
or omega-squared (Hayes & Winkler, 1971). This intraclass correlation is equivalent to the
R,, measure often used to evaluate occupational.survey task factor ratings. For raw ratings,
119