I struggled with the issue of defining "a school of  
economics" while researching William Whewell and the other  
early mathematical economists in Britain.  I concluded that  
while there were clear connections between these writers,  
still they did not consistitute a "school of thought"   
(hence the term the "Whewell GROUP of Mathematical  
Economists").    Drawing on Henry Spiegel, I argued that --  
"Fairly general agreement defines the sociological  
characteristics of a school of economic thought. Henry W.  
Spiegel, for instance, notes that a school consists of 'a  
recognized leader, a closely knit group of followers to  
exalt and spread the doctrines of the master, and a  
periodical to help in their dissemination.'  Such schools  
frequently have a geographic base, institutional links, and  
access to or control over a journal. Finally, 'the founders  
of influential schools devoted many years to their nurture' 
(Spiegel 1971, 183 - 184)."    While the Whewell Group  
shared several of these sociological characteristics,  
certain crucial elements were missing.  See James P.  
Henderson *Early British Mathematical Economics, William  
Whewell and the British Case* pp. 2 - 3. 
        I look forward to others' take on this issue 
 
Jim Henderson