conditions for tax collectors and greater freedom from political interference. Salary increases have been key to many reform programs, as an effort to improve staff recruitment and performance incentives. In other contexts, the focus has been on improving monitoring of staff and reducing opportunities for collusion and corruption. The simplest measures have focused on reducing faceto-face interactions between taxpayers and tax collectors through the introduction of selfassessments, automatized selection for audits, making tax payments online or at banks, and so forth. More ambitious efforts have relied on increasing internal audit capacity,<sup>54</sup> improving performance incentives,<sup>55</sup> or employing IT systems to introduce better data controls and to assess staff performance. Meanwhile, in extreme cases some local administrations have experimented with tax farming methods for smaller taxes – auctioning tax collection rights to independent contractors, who then retain any surplus revenue. This, however, raises fresh concerns about overhead costs, corruption at the contracting stage, lost revenues and arbitrary enforcement efforts.<sup>56</sup> There are signs that these reform efforts have yielded meaningful revenue gains across a number of countries. As was illustrated in Figure 1, tax collection has increased meaningfully over the past two decades across the developing world, and particularly in Latin America and Sub-Saharan Africa. These revenue gains have occurred across both direct and indirect taxes, though the most important gains have been from the VAT, which has been a focus of donor support and new investments. There is now, for example, emerging evidence of the impact of electronic tax registers in strengthening VAT compliance in low-income countries,<sup>57</sup> and the ability of higher capacity administrations to use the paper trails created by the VAT to strengthen compliance.<sup>58</sup> Even in places where progress has been slower overall, research has captured important successes if political commitment has been present: for example, some localities have successfully introduced and expanded digitized property tax systems,<sup>59</sup> while other administrations have expanded the use of third-party data for income tax enforcement.<sup>60</sup> Qualitatively, many senior tax administrators themselves have become defenders, and promoters, of the modernized approaches to enforcement introduced in recent decades – though others have continued to attempt to preserve more informal ways of working.

Nevertheless, reform results have been disappointing in many areas. While VAT performance has been relatively strong, total revenue gains have struggled to compensate for decreases in trade tax

> 54 Schreiber, L. (2018). Broadening the base: Improving tax administration in Indonesia, 2006-2016. _Innovations for Successful Societies_ . New Jersey: Princeton University.

> 55 Khan, A., Khwaja, A., & Olken, B. (2016). Tax farming redux: Experimental evidence on performance pay for tax collectors. _Quarterly Journal of Economics_ , (1):219-271.

> 56 Iversen, V., Fjeldstad, O-H., Bahiigwa, G., Ellis, F., & James, R. (2006). Private tax collection - Remnant of the past or a way forward? Evidence from rural Uganda. _Public Administration and Development_ , 26 (2):317-328.

> 57 Ali, M., Shifa, A., Shimeles, A., & Woldeyes, F. (2015). Information technology and fiscal capacity in a developing country: Evidence from Ethiopia. _ICTD Working Paper 31._ Brighton: International Centre for Tax and Development.

> 58 Pomeranz, D. (2015). No taxation without information: Deterrence and self-enforcement in the value added tax. _American Economic Review_ , 105 (8):2539-2569.

> 59 Jibao, S., & Prichard, W. (2015). The political economy of property tax in Africa: Explaining reform outcomes in Sierra Leone. _African Affairs_ , 114 (456):404-431; Cheeseman, N., & de Gramont, D. (2017). Managing a mega-city: Learning the lessons from Lagos. _Oxford Review of Economic Policy_ , 33 (3):457-477.

> 60 Carillo, P., Pomeranz, D., & Singhal, M. (2017). Dodging the taxman: Firm misreporting and limits to tax enforcement. _American Economic Journal: Applied Economics_ , 9(2) _: 144-64._

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