Letter from Dr. Prichard

Letter discussing journal article from British Journal of Radiology titled Deviation of Spinous Processe by Karel Lewit, MD

Taxing the Informal Economy: Challenges, Possibilities and Remaining Questions

Recent years have witnessed significantly increased attention to the challenge of taxing small businesses in the informal sector. However, much of this recent attention has remained focused on comparatively technical issues of revenue maximisation and policy design. This paper argues that this debate should focus increasingly on the wider development implications of informal sector taxation, as well as the political and institutional barriers to improved performance. When considering the merits of committing scarce resources to taxing small informal sector firms, debate has frequently focused on limited revenue potential, high costs of collection and potentially perverse impacts on small firms. By contrast, recent arguments have increasingly emphasised more indirect benefits of informal taxation in relation to economic growth, tax compliance and governance. These potentially broader benefits are increasingly finding support in recent research, but they are contingent on government support and consequently demand further attention. When we turn our attention away from whether tax authorities should tax small informal businesses towards the challenge of how to do so more effectively, we again argue that a broader frame of analysis is needed. Most existing research has focused on developing less distortionary tax regimes and on tax simplification in order to reduce the costs of compliance. However, while important, there strategies remain too narrow. Encouraging tax compliance demands not only lowering costs but also strengthening the potential benefits of formalisation, from increased security to new economic opportunities. As importantly, successful reform needs political support from political leaders, tax administrators and taxpayers alike. This demands greater attention to strengthening political incentives for reform, through strategic policy, administrative and institutional reform. With this in mind, the paper highlights a number of recent experiences that have sought to address these challenges, but which need further study

Taxing the Informal Economy: The Current State of Knowledge and Agendas for Future Research

This paper reviews the literature on taxation of the informal economy, taking stock of key debates and drawing attention to recent innovations. Conventionally, the debate on whether to tax has frequently focused on the limited revenue potential, high cost of collection, and potentially adverse impact on small firms. Recent arguments have increasingly emphasised the more indirect benefits of informal taxation in relation to economic growth, broader tax compliance, and governance. More research is needed, we argue, into the relevant costs and benefits for all, including quasi-voluntary compliance, political and administrative incentives for reform, and citizen-state bargaining over taxation

Test your surrogate data before you test for nonlinearity

The schemes for the generation of surrogate data in order to test the null hypothesis of linear stochastic process undergoing nonlinear static transform are investigated as to their consistency in representing the null hypothesis. In particular, we pinpoint some important caveats of the prominent algorithm of amplitude adjusted Fourier transform surrogates (AAFT) and compare it to the iterated AAFT (IAAFT), which is more consistent in representing the null hypothesis. It turns out that in many applications with real data the inferences of nonlinearity after marginal rejection of the null hypothesis were premature and have to be re-investigated taken into account the inaccuracies in the AAFT algorithm, mainly concerning the mismatching of the linear correlations. In order to deal with such inaccuracies we propose the use of linear together with nonlinear polynomials as discriminating statistics. The application of this setup to some well-known real data sets cautions against the use of the AAFT algorithm.Comment: 14 pages, 15 figures, submitted to Physical Review