What is necessary for the manifestation of expertise? According to Anthony Pym's tentative glossary of translation research terms*, expertise is "the performance of a task with a high degree of 1) socially recognized success, 2) efficiency and 3) holistic information processing", from which an added value is generated for the customer. While 1) and 2) are easy to understand, holistic information processing is understood by looking into cognitive sciences where this term adresses the way problems are solved on an expert level.
*From Translation Research Projects 3, ed. Anthony Pym, Tarragona: Intercultural Studies Group, 2011. pp. 75-110. http://isg.urv.es/publicity/isg/publications/trp_3_2011/index.htm