In general the economic cost of taxation increases with the tax rate and is higher when the base is narrow, as is the case in most developing countries. Reforms in developing countries such as Colombia, Indonesia, Jamaica and Malawi have concentrated on expanding the base, thus avoiding higher tax rates and adverse effects on incentives. To make the tax structure more transparent and to ease administration and enforcement, reforms have also favoured fewer rates and fewer exemptions. They have tried to promote equity by improving the collection of taxes from the wealthy through limited exemptions and improved tax administration and by avoiding taxes on the poor.
Successful tax reforms have demonstrated that variants of the value added tax (VAT) can generate substantial revenue with fewer distortions than import, turnover or excise taxes. Joint reform of trade and commodity taxes is particularly effective in meeting the dual goals of raising revenue and reducing inefficiency.
Many developing countries have a limited capacity for administration, so tax reform must be confined to what is administratively feasible. In most developing countries, especially the poorer ones, simplicity is essential; in particular, progressive income taxes are hard to collect. However, modern techniques, such as the use of computers and tax identification codes, can make it easier to collect most taxes. In fact, despite the technical problems, automation may eventually offer the most effective way to deal with expanded workloads in customs departments (with the growing volume and complexity of international trade), income tax departments (with the growing number of taxpayers) and treasuries (which need to forecast and monitor revenues). Such systems are currently being set up in Indonesia, Jamaica, Malawi and Morocco and are already partially or fully operational in Brazil, Ecuador, Honduras, Korea, and Nigeria. Experience suggests that automation can increase the efficiency of well-run operations, but it can exacerbate problems if superimposed on badly organized administrations.
Another approach is to improve information exchange among tax-collecting agencies. Exchange of information between revenue departments is highly advisable because gross sales figures are important in determining income tax liabilities, and valuations of sales for income tax purposes make it easier to implement [ad valorem] excises and duties. However, in both developing and industrial countries, import duties and taxes on domestic transactions or sales and income taxes may be administered by separate departments, with little or no exchange of information. Although a totally linked, self-checking system of taxes is still not possible, the availability of personal and mini-computers makes the use of self-enforcing taxes, matching information from different sources, more feasible. It is now possible for information furnished by one taxpayer to reveal the receipts and gains made by other taxpayers, as, for example, in a VAT.
A tax analysis unit can support policymakers by analysing the revenue consequences of changes in exchange rates, interest rates and trade and industrialization policies - all of which affect tax bases and interact with tax rates. It can also weigh the implications of new revenue measures for other policies and forecast revenue to assist in fiscal planning. Such units feature in many tax reform programmes.
Country-specific needs will determine whether comprehensive or partial reform is required. Comprehensive reforms need not be avoided on the grounds of overloading administrative capacity. The elements of a comprehensive reform can be introduced simultaneously or in stages in the light of revenue and administrative constraints. New tax instruments have been introduced successfully, as in Colombia and Korea. However, implementing a tax change is likely to be easier if the reform builds on existing tax instruments, as in India and Malawi.