The increasing focus on domestic resource mobilization in developing countries means that, for researchers and policy makers, access to accurate and timely data is more important than ever. The Government Revenue Dataset (GRD)--developed by the International Centre for Tax and Development and now maintained by UNU-WIDER--remains the most complete source of cross-country data available and has already been used extensively to address questions surrounding the impact of tax policy on development.
"Good policies require good research and good research requires good data"
The latest version of the GRD was launched at the beginning of July 2017. The dataset has undergone extensive revisions since the last version and so I'm here to provide a quick summary of what's new. The GRD now contains data for over 190 countries, up to the year 2015. Fiscal data often lags 12-18 months behind the calendar year, so we have incorporated the most recent data available from the usual international sources. But in addition to just adding more observations, additional improvements have been made to enhance the consistency and accuracy of the data, along with improvements to accessibility for users. Indeed, in addition to adding data for 2013-15, we have also increased the total number of observations available for previous years, in particular for sub-components of total tax, such as income taxes, taxes on goods and services or trade taxes. But let's start with a look at what the data itself reveals about revenue collection in recent years.
Data trends--the good and the bad news
So what kind of trends can we see emerging in the data? Well, the news for many developing countries continues to be positive. In low-income countries, non-resource taxes have, on average, increased year-on-year in all but two years of the last decade. A similar upward trend can be seen for the average middle-income country. In LICs, the average amount of tax collected in 2015 was just over 14% of GDP --an average increase of almost 2% of GDP in just 5 years --quite impressive progress considering the relative stagnation of tax revenues in LICs in previous decades.
When we look at the tax ratio by region, there is also some good news. Sub-Saharan Africa--by far the world's poorest region as measured by per capita GDP--is actually not doing too badly at collecting taxes, at compared to some other regions. On average, sub-Saharan African countries collect more than those in...