This essay sketches technical and non-technical issues around persistent identifiers (henceforth PIs) in a manner which makes no attempt to be complete. Our goal is to rescue the core notions from the obscurity which detail and completeness burdens them with. A reader willing to entertain the...

We present the operationalized Toll Index, which is a new type of early indicator for the German business cycle. We present the basic idea and document the power of the indicator for the purpose of nowcasting. The data will be regularly available at the IDSC, the data bank center of IZA and will...