Aspects estimate attributes of physical movement of a user from motion data acquired from a unique activity tracker deployed and operational on the user while the user is proximate to a work-piece receptacle; compare the estimated physical movement attributes to a knowledge base plurality of discrete data sets of motion attribute value that are labeled with specific physical movements; identify portions of the estimated physical movement attributes that match labeled knowledge base data sets associated to execution of a defined work unit associated to a work-piece receptacle during a defined working time period; in response to notice of completion of a work unit, and credit the user with a compensation value of for completion of the work unit in response to verifying that an aggregation of the portions matches a threshold requirement for indication of completion of work unit.