Measurement of public sector enterprises' performance, especially efficiency measurement by way of a DEA model, has gained prominence in recent years among academics and practitioners. However, the different sources of input and output chosen to be used in the DEA model would produce different results for the assessor. The current research uses a closed-ended questionnaire aiming to explore suitable sources of input and output for use in a data envelopment analysis (DEA) model to assess the efficiency of public sector commercial banks (PSCBs) in Vietnam. The data is subsequently analysed quantitatively using confirmatory factor analysis (CFA) with the AMOS program. The results show five sources of input and five sources of output suitable for inclusion in the DEA model. This paper provides a reliable basis for policy analysts and performance assessors to use DEA to analyse efficiency and effectiveness in PSCBs and might trigger future research on efficiency evaluation of PSCBs using DEA in the context of Vietnam.