The graduates survey conducted by the German Centre for Research on Higher Education and Science Studies (DZHW, formerly HIS) since 1989 are nation-wide representative logitudinal anlayses sponsored by the Federal Ministry of Education and Research. Results are only available in German at this time.
Until 2010, the Bologna reform claimed that higher education degrees, the German Diploma most notably, had to be migrated to the Bachelor/Master system. As of December 2009, the Cologne Institute of Economic Research (IW) surveyed companies employing engineers to determine the acceptance of the new degrees. Results indicate that acceptance is generally high.
The monitorING data base contains a lot of useful information regarding higher education. Many selection criteria allow for an individual information retrieval concerning engineering students and graduates in Germany. The data base itself is unfortunately only available in German language.