Dana Broach

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Public Law 92-297 requires that air traffic control specialists (ATCSs), hired on or after May 16, 1972, retire at age 56. This law is based on testimony given in 1971 that as controllers aged, the cumulative effects of stress, fatigue (from shift work), and age-related cognitive changes created a safety risk (U.S. House of Representatives, 1971). The hypothesis has been considered in two studies of en route operational errors (OEs) with contradictory results (Center for Naval Analyses Corporation (CNAC), 1995; Broach, 1999). The purpose of this re-investigation was to test the hypothesis that controller age, controlling for experience, was related to the occurrence of OEs using a statistical method appropriate for rare events. A total of 3,054 usable en route OE records were extracted from the FAA OE database for the period FY1997 through FY2003 and matched with air route traffic control center (ARTCC) non-supervisory controller staffing records, resulting in a database of 51,898 records. Poisson regression was used to model OE count as a function of the explanatory variables age and experience using the SPSS® version 11.5 General Loglinear (GENLOG) procedure. The Poisson regression model fit the data poorly (Likelihood Ratio χ2 = 283.81, p < .001). The odds of OE involvement, estimated with the Generalized Log Odds Ratio, for older controllers (GE age 56) were 1.02 times greater than the odds for younger (LE age 55) controllers, with a 95% confidence interval of 0.42 to 1.64. The range of odds indicated that neither age group was less or more likely to be involved in an OE, controlling for experience. This analysis does not support the hypothesis that older en route controllers are at greater risk of involvement in an OE. This finding suggests that the original rationale for the mandatory retirement of ATCSs may need to be re-evaluated. Additional research is recommended.