Influence of Internal Control Systems Mechanism in Reducing Ethical Breaches in Public Tertiary Institutions

Public tertiary institutions in Nigeria face persistent challenges with ethical breaches, including fraud and policy violations, which undermine their integrity and mission. This study investigates the influence of key internal control system (ICS) mechanisms—Segregation of Duties, Control Activities, and Information & Communication—on reducing these ethical breaches, measured through adherence to codes of conduct, prevention of policy violations, and overall improvement in ethical compliance. Employing a quantitative, ex-post facto design, data were collected via a structured questionnaire from 179 key administrative and financial staff across public tertiary institutions in North Central Nigeria. Data were analyzed using descriptive statistics, correlation, and multiple linear regression. The findings reveal that Information & Communication had the strongest significant effect on Adherence to Code of Conduct (β = 0.526, p<0.001), explaining 51.5% of its variance. Control Activities (β = 0.381, p<0.001) and Segregation of Duties (β = 0.291, p<0.001) were the most significant predictors for the Prevention of Policy Violations (R² = 0.565). For overall Improvement in Ethical Compliance, Information & Communication (β = 0.359, p<0.001) and Control Activities (β = 0.290, p<0.001) were the principal drivers (R² = 0.483). The study concludes that ethical breach reduction is not achieved by structural controls alone but is fundamentally dependent on a transparent, well-communicated, and integrated internal control environment. Therefore, institutional reforms must prioritize strengthening communication channels and transparency alongside traditional control activities to cultivate a sustainable culture of integrity.