Readers respond

MPG discrimination story draws response; researcher clarifies comments on power laws

Mar 9, 2004
The Editor(

To The Editor:

Citing statements made by a former scholarship student at a Max Planck Institute, an article in The Scientist alleged that the Max Planck Society (MPG) discriminates against foreign Ph.D. students by granting them scholarships, whereas German Ph.D. students receive work contracts. The cited scholarship student has taken his case against the MPG to labour court.

Indeed, the MPG does employ German Ph.D. students with work contracts, whereas foreign Ph.D. students are granted scholarships. The net payments made are more or less comparable in both cases. The differences arise in terms of social security. While work contracts are subject to social security benefit payments, scholarships are not. The two arrangements, however, are completely different in their design and intent, and also entail entirely different obligations. Ph.D. students on regular employment contracts are under obligation towards the MPG to perform a defined scope and volume of work. Ph.D. students on scholarships, however, are not obligated toward the MPG to undertake a defined amount of work. The scholarships represent a contribution towards livelihood, intended to assist such students in conducting their research work at one of the Institutes.

The differentiating rules result historically from the situation whereby formerly non-German Ph.D. students usually had no interest in integrating into German social security schemes, either because they were only spending a short period of time at a German institute, or because they were planning to return to their native country. This situation has changed incrementally over time, among other reasons due to a number of international transition agreements that were concluded concerning social security issues. The alternative of scholarships and the latitudes they offer are necessary, as in many instances there is no requirement and also no interest on the part of the scholarship student of becoming more closely involved with and integrated into the respective institute, and preference is given to the greater flexibility that scholarships offer.

The Max Planck Society, however, is taking steps geared to giving better consideration to the needs for stronger differentiation and intends, according to the defined contents and scope of individual relationships between institutes and Ph.D. students, to offer work contracts or scholarships to German and non-German nationals alike. Existing contracts and scholarships shall remain unaffected. A respective resolution has already been passed. The responsible Federal government and Federal state bodies will already be addressing these issues this March.

Rüdiger Willems (

Max Planck Society, Head of the Department of Personnel and Legal Affairs

To The Editor:

I would like to clarify some comments I made that could be interpreted as criticism of the paper by Ueda et. al. that was the subject of an article on March 3. On the contrary I thought that the research was quite interesting, from my limited, non-biologist point of view.

The fact that people are rediscovering power laws is not a problem, rather it is a consequence of large datasets becoming available at different times in different fields. In the late 19th to mid 20th century, power laws were observed for income distributions and the frequency of words in text, because those were some of areas where statistics were abundant. In the past decade, the Internet has become a new source of data. Power laws were observed in the popularity and size of web sites, and the link distributions of the web graph and email networks.

Over time, many models have been proposed for the dynamics that lead to the observed regularities, and many of them share the feature of proportional growth. Now, automation and parallelization in experimental biology have provided an abundance of data to show that metabolic networks and, in the work of Ueda et. al., gene expression dynamics, are also governed by power-laws. There is every reason to believe that modeling the processes underlying the statistical properties of these biological systems will have significant impact, just as it has in other fields.

Lada A. Adamic (

Hewlett-Packard Laboratories