To successfully perform systems engineering tasks, systems engineers need a systems view or, in other words, a high capacity for engineering systems thinking (CEST). A tool for assessing systems thinking of engineers, once validated, may be used for systems engineering workforce selection and development, developing systems engineering curriculum, and education and training programs and a standard tool for assessing systems engineers' competencies. Since there is no known way for directly 'measuring' systems thinking in general and CEST in particular, an indirect way is needed. This paper proposes an idea for developing an indirect means, i.e. a questionnaire for assessing the CEST of systems engineers. The idea is composed of four logic layers.