Rank approach to analyze data from the u.s. department of energy's illness and injury surveillance program

The U.S. Department of Energy's (DOE) Illness and Injury Surveillance Program (IISP) has monitored the health of its contract workforce at selected DOE sites since 1990. The goal is to monitor morbidity in, and assess the overall health of, the DOE workforce to identify groups that may be at increased risk for occupational illnesses and injuries. More than 20 years of IISP data allow trend analyses and comparisons within and among DOE sites. However, common limitations of health surveillance data exist. In particular, data quality, completeness, and site adherence to reporting requirements change over time and vary by site. Trend analyses using common measures such as rates of illnesses and injuries may not be appropriate and may produce misleading results. Therefore, a rate rank approach, which ranks annual rates of cancers by occupations for example, is explored. Since rank is a relative measure, it is less affected by the data quality concerns and limitations of the IISP. A set of rank-based analytical methods including a Monte Carlo statistical test for rank changes over time are developed to assess health conditions of the DOE workforce. One specific application is to examine rate ranks from a given year have changed significantly from another year or baseline ranks.