Search online for information about a balanced economy, or a balanced diet, and page after page is listed.  Look for a balanced teaching staff, and the options are somewhat more limited.  Because, like everything that is best, beauty lies in the eyes of the beholder. What constitutes a balanced teaching staff?  Perhaps the best definition has two parts.  Quality and sustainability. It was hard to understand why the local authority had put the little village primary into special measures.  Equally,…