Séminaire de groupe
|Critical mass and the dependency of quality on quantity in research|
|mardi 21 juin 2011 , 10h25|
|Salle de séminaire du groupe de Physique Statistique|
The notion of critical mass in research is one that has been around for a long time without proper definition. It has been described as some kind of minimum, threshold group size above which research standards significantly improve. However no evidence for such a threshold has been found and critical mass has never been measured – until now. We present a new, simple, sociophysical model which explains how research quality depends on research-group structure and in particular on size. Our model predicts that there are, in fact, two critical masses in research, the values of which are discipline dependent. Research quality tends to be linearly dependent on group size, but only up to a limit termed the “upper critical mass”. This is interpreted as the average maximum number of colleagues with whom a given individual in a research group can meaningfully interact. Once the group exceeds this size, it tends to fragment into sub-groups and research quality no longer improves significantly with increasing size. There is also a lower critical mass, which small research groups should strive to achieve for stability. Our theory is used to compare Britain’s Research Assessment Exercise (RAE) to the French AERES evaluation system and they are seen to be compatible at faculty level, though the British method yields more detailed information at the level of groups or departments. RAE empirical data are then used to test the relationship between quantity and quality of research groups, for which critical masses are determined. These are discipline dependent. For pure mathematics the upper critical mass is about 4, for applied mathematics and theoretical physics it is 13, while for experimental physics it is 25. The lower critical masses are about half the upper values.