penalties were thus the keys to inducing compliance.<sup>8</sup> Over time these models came to be complemented by an expanded focus on facilitating tax compliance, recognizing that taxpayers were more likely to comply when doing so was straightforward and low cost, thus shifting the rational economic calculus in favor of compliance.<sup>9</sup> This focus on enforcement and facilitation has underpinned a range of desirable reforms across the developing world, along with modest, but consistent, revenue gains. Efforts to strengthen enforcement have included investments in building expanded assessment and audit capacities, new IT systems designed to reduce the scope for avoidance, improved collection methods, efforts to expand access to third-party information, and policy changes designed to reduce the scope for evasion.<sup>10</sup> Meanwhile, efforts to facilitate compliance – and emphasize “customer service” – have correspondingly sought, among other aims: (a) to simplify tax systems, and related reporting requirements; (b) to provide easy access to information about tax liabilities; (c) to provide access to support and advice; (d) to provide simple methods for making tax payments, including online, at banks and via SMS; and (e) to reduce face-to-face interactions with tax collectors, which have historically caused delays and increased the risk of abuses.<sup>11</sup> The priority given to these issues is reflected, for example, in the World Bank’s Doing Business surveys, which track the difficulty of tax compliance for businesses.<sup>12</sup> Finally, reform efforts have not only targeted tax _payers_ , but also sought to improve the effort and performance of tax _officials_ , in order to reduce collusion, corruption and simple shirking. These have included pay increases, performance contracts, increased monitoring, efforts to reduce opportunities for corruption and collusion, and a broad emphasis on strengthening the “customer orientation” of tax administrations.<sup>13</sup> However, despite important successes, efforts to strengthen enforcement and facilitation have not been sufficient to deliver more effective, equitable and accountable tax systems. The taxation of the wealthy remains highly ineffective in much of the developing world, with collection of personal income taxes at only about a quarter of the levels found in OECD countries – this represents the largest gap in comparative revenue mobilization (Figure 4). Subnational tax systems generally fail to generate significant revenues, especially from property taxes, while in areas of weak governance there is mounting evidence of heavy burdens on lower income groups created by user fees and demands for informal payments.<sup>14</sup> While value-added taxes have been hailed as

> 8 Cummings, Ronald, G., Martinez-Vazquez, J., McKee, M., & Torgler, B. (2009). Tax morale affects tax compliance: Evidence from surveys and artefactual field experiment. _Field Experiments in Economics_ , 70 (3):447-457.

> 9 Alm, J., Cherry, T., Jones, M., & McKee, M. (2010). Taxpayer information assistance services and tax compliance behavior. _Journal of Economic Psychology,_ 31 (4):577-586; Alm, J. & Torgler, B. (2011). Do ethics matter? Tax compliance and morality. _Journal of Business Ethics_ , 101:635-651.

> 10 Slemrod, J. (2018). Tax compliance and enforcement. _NBER Working Paper No. 24799_ . National Bureau of Economic Research. 11 Fjeldstad, O.-H. & Moore, M. (2008). Tax reform and state building in a globalized world, in D. Brautigam, O.-H. Fjeldstad & M. Moore, (Eds), _Capacity and Consent: taxation and state building in developing countries_ . Cambridge: Cambridge University Press, 235–60.

> 12 World Bank & PwC. (2018). Paying taxes 2019: Fourteen years of data and analysis of tax systems in 190 economies: How is technology affecting tax administration and policy? Washington: The World Bank.

> 13 Mookherjee, D. (1998). Incentive reforms in developing country bureaucracies: lessons from tax administration. _Annual World Bank Conference on Development Economics 1997_ , Washington: World Bank, 103-138; Fjeldstad, O. H. (2003). Fighting fiscal corruption: lessons from the Tanzania Revenue Authority. _Public Administration and Development: The International Journal of Management Research and Practice_ , 23(2), 165-175; Raballand, G., Chalendard, C., Fernandes, A., Mattoo, A., Rijkers, B., (2017). Customs Reform and Performance Contracts: Early Results from Madagascar. _Governance Notes, No. 2_ .

> 14 Bird, R. (2011). Subnational taxation in developing countries: A Review of the Literature. _Journal of International Commerce, Economics and Policy_ , 2 (1):139-161; Franzsen, R., & McCluskey, W. (2017). _Property tax in Africa: Status, challenges and_

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