Testing and refining nutrition screening tools that have demonstrated validity and reliability is important to ensure that mechanisms for allocating nutrition resources to those most in need are as efficient as possible. Using structural equation modelling, a nutrition screening instrument for community-dwelling seniors (SCREEN II) was tested to determine its factor structure and to understand how it measures nutrition risk. Further, this analysis was completed to identify a model that works equivalently for men and women and older and younger seniors. The screening tool was completed by 190 men and 417 women. Age groups (50-74 years, and 75+ years) were evenly split. Dietary intake and challenges influencing intake were identified as two factors representing the screening items. The final model showed good fit when tested for all participants. The model contained a core group of risk factors within SCREEN II that showed sex and age invariance. This set of risk factors can help guide refinement of nutrition screening instruments and is useful for health professionals to consider regularly as they work with community-dwelling older adults.