Medication error harms approximately 1.5 million people every year with the cost of treating a drug-related injury around $3.5 billion yearly. Awareness and scrutiny of medication error incidence within acute care settings has increased over recent years but identifying variable contributions to the incidence has become more complex. The purpose of this study was to examine the relationship between work group effectiveness, practice environment, workload, nursing, contextual factors and medication error incidence on medical-surgical units. The Quality Health Outcomes model served as the overarching framework for the study. Multifactorial correlational design was selected to evaluate variable relationships. Various methods were employed to collect data, including surveys and database extraction. The Comprehensive Assessment of Team Member Effectiveness (CATME), Practice Environment Survey – Nursing Work Index (PES-NWI), and Unit Profile Survey were collected from nursing personnel to evaluate work group effectiveness, practice environment, and workload. Established databases provided information on nursing factors (age, years of experience, and educational status), contextual factors (turnover, admission, discharge and transfer rate) and medication error incidence. Spearman Rank correlation coefficients were calculated with statistically significant relationships (p-value <.05) identified with work group effectiveness, practice environment, age, years of experience, and transfer out to medication error incidence. Increases in work group effectiveness, practice environment, and transfer out resulted in increases in medication error incidence. Conversely, increases in age and years of experience resulted in decreases in medication error incidence. Measurement methods implemented for group member effectiveness, practice environment and workload weakened the results of the correlations. Missing protocols and accuracy checks for database information diminished the strength of the relationships of nursing and contextual factors to medication error incidence. Medication error was evaluated by self-report methods, limiting the overall validity of the study. Opportunities for future research are infinite with immediate attention needed for an improved method to measure workload and implementation of objective processes for identifying medication error incidence in acute care settings.