Ultimately, innovative approaches are needed to overcome persistent technical _and_ political barriers to improving tax compliance. These approaches would also contribute to expanding the broader public benefits of taxation through complementary investments in enforcement, facilitation and trust. The Innovations in Tax Compliance project correspondingly seeks to develop a conceptual framework that links these competing needs into a holistic vision for approaching tax reform. No individual component of this framework is, in and of itself, particularly novel or transformative. Indeed, the very best reform programs likely already do much of what is proposed here, though often in more _ad hoc_ ways. The key value added of the framework lies in unifying relatively siloed and fragmented strands of research, embedding discrete research findings in a holistic framework for reform, developing tools to consistently transform these research insights into operational outcomes, and providing a platform for conducting systematic research into the effectiveness of these approaches to reform.

This more holistic approach to reform is likely to imply the development of more targeted and locally-specific reform strategies. The approach would identify the “binding constraints” on reform and develop targeted strategies for overcoming them. Identifying binding constraints implies understanding, in any particular context, what explains poor outcomes – that is, how much do different factors matter, in what ways, and in what combinations? Many successful interventions have been shown to be effective under certain circumstances.<sup>34</sup> A key goal of this framework is to help policy makers to think about the right combination of strategies in specific contexts, and thus to allocate resources most effectively. In some cases, there may, for example, be significant technical capacity in place, but little political support for reform – necessitating a focus on shifting the politics of reform rather than on technical capacity building. In other cases, there may be significant political support for reform, but limited technical capacity – with potentially large payoffs to investing in technical support. It is also possible to have significant technical capacity and political will, but major concerns about equity or accountability, thus necessitating strategies seeking to build trust and support the construction of more inclusive fiscal contracts among specific segments of taxpayers. Meanwhile, across all these scenarios, a focus on “binding constraints” seems likely to encourage simplicity and a focus on the basic building blocks of effective reform, which have in many areas proven stubbornly difficult to put in place.<sup>35</sup> The remainder of this paper develops a formal framework that combines enforcement, facilitation and trust to develop more effective approaches to tax reform. This underpins a broader project that will explore the framework’s application to specific tax segments and types, develop operational tools for its deployment in the field, and seek to systematically study the framework’s impacts in specific countries. The paper is organized as follows. The next section provides an overview of the full framework. The third section provides a more detailed discussion of the roles of enforcement, facilitation, and trust in shaping tax compliance. The final section discusses concrete

> 34 For example: Mascagni, G., Nell, C., & Monkam, N. (2017). One size does not fit all: A field experiment on the drivers of tax compliance and delivery methods in Rwanda. _ICTD Working Paper 58_ . Brighton: International Centre for Tax and Development; Khan, A., Khwaja, A, & Olken, B. (2016). Tax farming redux: Experimental evidence on performance pay for tax collectors. _Quarterly Journal of Economics_ , 131 (1):219-271; Touchton, M., Wampler, B., & Peixoto, T. 2019. “Of governance and revenue: Participatory institutions and tax compliance in Brazil.” _World Bank Policy Research Working Paper 8797._ Washington: World Bank.

> 35 Moore, M, & Prichard, W. (2017). How can governments of low income countries collect more tax revenue? _ICTD Working Paper 70_ . Brighton: International Centre for Tax and Development; Moore, M., & Prichard, W. (2017). Tax reform that fits in lowincome countries: Five ideas for simplifying tax systems to fit local realities. _ICTD Summary Brief 17_ . Brighton: International Centre for Tax and Development.

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