One notable aspect of the term "school" is its typically negative valence.   
How often do economists willingly identify themselves with a school?  Not  
often, I think.  The term is usually reserved for one's opponents, who have  
ceased to engage the facts and now engage only one another.  For example when  
Friedrich List referred to Smithians again and again simply as "the School",  
no reader could have mistaken it for a compliment. 
 
To return to the original query: while I wouldn't say that opprobrium is  
either a necessary or sufficient condition for use of the term "school",  
there is a strong historical association.  For this reason I have reservations  
about its usefulness in calm discourse. 
 
Heath Pearson