Modern Japanese firms must build a Human Resource Portfolio Model (HRPM) that combines diverse worker categories according to criteria, such as (1) skill enhancement (work execution potential) through continued service and (2) work allocation, that go beyond the framework of employment status, instead of preserving a simple dichotomy based on two types of employment status: standard workers who perform core work and non-standard workers who perform peripheral work. The specific objectives of this research are to (1) develop a logical HRPM with reference to previous research concerning human resource portfolios, (2) develop HRPM measurement criteria and experientially verify whether they are realistic, (3) use the HRPM confirm the relationship between purposes of employment and qualitative utilization, (4) use the HRPM to confirm the relationship between qualitative utilization and equitable treatment, and (5) use the HRMP to reexamine the meaning of qualitative utilization of non-standard workers.
An analysis of the answers to questionnaires that were mailed to 459 businesses in Osaka Prefecture revealed the following: (1) Qualitative utilization of non-standard workers is not seen in terms of the “overlapping of work” with existing standard workers, but can be grasped using a logically derived HRPM that also includes standard workers. (2) As qualitative utilization progresses, both the firm-specific human assets required of non-standard workers and the non-separability of work relations increase, but that equitable treatments react only to the former. It is presumed that this is because rather than performing “job enrichment” as the skills of their non-standard workers develop, businesses perform “job enlargement” while maintaining the vertical division of labor relationship between standard and non-standard workers. (3) It is important that the HRPM is seen not as a static equilibrium reflecting the overlap “right now” of work content and responsibilities, but from dynamic, individual angles whereby quadrants move flexibly in line with individual workers’ expectations concerning their development of specific skills and promotion to more challenging work in the future.