Tax Enforcement, Deterrence Theory, and the Behavioural Foundations of Tax Compliance in West Africa

This doctoral study develops a comprehensive theoretical synthesis and empirical investigation of tax enforcement, deterrence theory, and the behavioural foundations of compliance, drawing on evidence from Nigeria and a comparative West African sample. Classical deterrence theory, grounded in the Allingham-Sandmo model, predicts that compliance increases monotonically with audit probability and penalty severity, yet decades of empirical evidence reveal that behavioural factors including tax morale, social norms, procedural fairness, and institutional trust exert independent and sometimes dominant effects on compliance decisions. This study develops an extended compliance model integrating deterrence, social capital, and legitimacy mechanisms, estimated using a multi-country experimental and survey design covering Nigeria, Ghana, and Senegal. A survey experiment administered to 1,200 taxpayers across the three countries uses randomised vignettes varying audit probability, penalty severity, peer compliance information, and procedural fairness cues to decompose the relative contribution of deterrence and behavioural mechanisms to stated compliance. The structural model is estimated using Bayesian hierarchical modelling, allowing cross-country parameter heterogeneity while pooling information across samples. The study expects to find that behavioural mechanisms, particularly social norm adherence and procedural fairness perceptions, explain at least as much compliance variance as deterrence factors in the West African context, with significant between-country heterogeneity reflecting differences in institutional trust. Theoretical contributions include the West Africa-calibrated extended compliance model and the regional multi-country compliance experimental dataset. Keywords: deterrence theory, tax enforcement, behavioural compliance, West Africa, experimental design.