This thesis provides a structure for understanding the various issues in the design and implementation of a petroleum tax system. Its main objective is to examine whether the Nigerian petroleum tax system is appropriately designed to achieve the benefits the country desires from its petroleum contractual arrangements. Informed by the literature reviewed, economic rent theory was adopted as a theoretical framework in the thesis. While other theories could have been applied as a framework, economic rent theory was deemed to be most appropriate because taxes levied on economic rent are not generally perceived to act as a disincentive to the initiation or continuation of business operations. Informed views on the petroleum fiscal system used in Nigeria were sought from a range of "experts" in the field via a large scale questionnaire. The empirical data collected were then subjected to statistical analysis to determine the overall response patterns of the respondents for each of the 58 variables surveyed. This analysis enabled tentative conclusions to be drawn about the validity of various hypotheses developed in the thesis. Further analysis was carried out to determine and critically assess statically significant responses between respondent groups. The study revealed that the Nigerian petroleum taxation system was viewed as being well-designed, insofar as it protects the interests of both the government and the international oil companies operating within Nigeria. Furthermore, the "expert" respondents were of the view that a majority of the measures put in place to ensure compliance with the petroleum taxation system have been effective. However, the study revealed differences in views amongst the various groups of "experts" to some questions which suggests that some groups may have articulated views based on partisan values. The differences suggest that the different groups may have vested interests in the petroleum taxation system. Given the role these groups play in the petroleum fiscal system in Nigeria, it is argued that these vested interests may well have negatively affected the design and operation of the petroleum fiscal system. This finding may have important implications for the future design and operation of the Nigerian petroleum taxation system. The literature reviewed and survey data analysed resulted in a number of conclusions. First, it is argued that it is very difficult to make a single petroleum tax system that serves the needs of different countries. Second, it is suggested Nigeria‘s petroleum tax regime is predicated upon a desire to capture as much revenue as possible for the government. Third, the thesis concludes that the implementation processes of the Nigerian petroleum tax system are fundamentally weak and require further improvement. Fourth, it is also the conclusion of this thesis that the Nigerian petroleum tax system lacks the capacity for timely review. Finally, it is shown that the Nigerian petroleum tax system is sensitive to changes in tax regulations across oil producing countries.

This study investigates the impact of aspects of tax design on the operating costs of the tax system. The thesis focuses on the Australian and UK regimes for taxing the capital gains of individuals. It contends that the compliance burden faced by personal taxpayers and the administrative costs incurred by revenue authorities are directly influenced by the design of the capital gains tax ('CGT') regimes in each country. The study bridges the divide between theoretical analysis of CGT and empirical studies on tax operating costs. It uses a hybrid research design to test a series of hypotheses that emerge from a review of the literature and the experience of the researcher. It combines a technical analysis of the relevant Australian and UK legislative provisions (including an analysis of the policy and other background data that underpins those provisions) with empirical research on the views and experience of practitioners who are responsible for the operation of the legislation in the two countries. The results obtained from this combined methodology indicate that the operating costs of taxing capital gains in Australia and the UK are directly affected by the design of the legislative provisions. Moreover, the study outcomes indicate that operating costs in both countries are high (on a number of comparative measures), have not reduced over time, and are both horizontally and vertically inequitable. The research indicates that the primary factors that cause the high operating costs include the complexity of the legislation and the frequency of legislative change, together with record-keeping and valuation requirements. The thesis identifies specific legislative changes that would address operational cost concerns. These include the phasing out of the 'grandfathering' exemption together with the introduction of an annual exempt amount, and the rationalisation of business concessions in Australia; and the abolition of taper relief and its possible replacement with a 50% exclusion in the UK. More importantly, it seeks a more principled approach to the taxation of capital gains in both countries, and emphasises that legislative change can and should only be enacted with a full and clear understanding of the operating cost implications of that change.

Transportation economists apply different labor supply models when studying anti-congestion policy: (i) endogenous working hours; (ii) endogenous workdays but given daily working hours; (iii) labor supply as a residual. We study whether the outcome of anti-congestion policies that change the relative cost of labor supply margins, and, thus, may affect decisions on working hours and working days, is robust against the model applied. In particular, we focus on welfare implications in the presence of other taxes when there is a congestion externality. We find surprisingly strong differences in quantity and sign. Further, we develop a clear recommendation for future research on issues that include decisions on commuting trips. Researchers shall apply both a model of endogenous working hours that provides an upper limit and a model of endogenous workdays that provide a lower limit of results for welfare changes, optimal policies and two optimal tax components (Pigouvian and Ramsey terms).