Using GATB (and similar) Results for Aptitude Adjustments
Rationale: The General Aptitude Test Battery (GATB) was constructed to measure 9 of the 11 aptitudes used to describe typical aptitude requirements of occupations. The GATB assumes that aptitudes are normally distributed across the population. GATB performance is reported in standard scores.
SkillTRAN encourages the practitioner to add one Standard Error of Measurement (SEM) to each standard score before converting to an approximate DOT Aptitude value level. The following conversion table is statistically derived.
TEST SCORE CONVERSION GUIDE
Aptitude levels are most accurately set when performance on test items (whether GATB or GATB-like instruments) is matched to the example statements associated with each level of the aptitude factors. See the RHAJ Chapter 9 for these statements.
Impact: Increasing actual test performance by one SEM before estimating the DOT level helps to identify more occupational choices for an individual. Use a value of 4 as the minimum value assigned to avoid being unnecessarily restrictive, unless injury or disability absolutely precludes any ability in that factor (e.g. a person with quadriplegia has no eye-hand-foot coordination). While aptitudes may be normally distributed across the population, they are not normally distributed across the occupational database. Be sensitive to the distribution of aptitudes as detailed in the DOT Pocket Guide.
SPECIAL NOTE: If test performance is less than the aptitude performance suggested by work history, use the work history values unless a permanent injury has caused the poor test performance. Work history is often a more reliable measure of performance than testing.