47 - The debt brake stands on feet of clay

Unsichtbares Akkordeon

A more conventional weighting would have done less damage to their reputation.


Researchers Kenneth Rogoff and Carmen Reinhard of Harvard University postulated in 2010 that exceeding the national debt by 90% of economic output has a negative impact on a state's economic growth. This basic assumption is both the basis of the German debt brake and the austerity requirements of the Euro rescue policy. However, an attempt to replicate the result based on the underlying data did not succeed. In fact, the 2010 study did not include data for specific years, weighted some cases abnormally high, and inadvertently failed to include several countries.

The media echo that followed the failed replication significantly damaged the reputation of the two economists. Nevertheless, in the replication study as well as in a follow-up study of the Harvard researchers, the fundamental connection remained, although the reduction in growth rates was less severe than originally calculated.


This example shows that individual decisions in the course of data analysis must be well documented and mentioned in the associated publications in order not to raise the suspicion of data manipulation in favour of particularly spectacular or significant results. Pre-registration of studies in a journal is also a good step towards having research questions, research design and implementation independently assessed.