In many countries, public organisations are among the largest creators and gatherers of data. To increase economic growth, governments have therefore begun to liberate access to large parts of government data by developing open government data (OGD) initiatives. Since the emergence of OGD initiatives, many OGD portals have been launched. There is a common belief that sharing OGD throughout platforms would be sufficient to motivate companies to re-use data and improve economic growth. However, there is very little evidence about the quality of shared OGD. For companies to be able to re-use, share and create value from OGD, data publishers must meet certain good practice standards. Following a pragmatic research approach, in this paper we present an index that can be applied for the quality assessment of the published OGD on portals. On the basis of 17,777 published data resources gathered from the Swiss OGD portal (opendata.swiss), we demonstrate the logic of the index and discuss the key learnings we obtained from applying the index to this concrete case. We conclude that, in Switzerland, the adherence to good practice standards for publishing OGD is fairly low.