Recent studies report about the need for and difficulties in measuring technical working skills among vocational high school students worldwide (Mabed & Köhler, 2018). Often the discussion is linked to the question of skills versus competencies, not only in the context of new digitized forms of measurement. Furthermore, a growing number of completely new or updated measurement procedures is about to reach the TVET sector in the context of the digitization of TEL (Köhler & Drummer, 2018; Hariyanto & Köhler, 2017). This study aimed at investigating the differences of the technical skills of vocational high school students majoring in construction drawings engineering in industrial working practices. As an empirical approach for their evaluation study authors used a discrepancy evaluation model. The population of this study consisted of 195 students in Yogyakarta and Sleman, Indonesia. A proportional random sampling was used to select 124 students from the population with both, the industrial work and the students becoming the sources of the information. The data analysis process was done using descriptive analysis and Wilcoxon matched pairs test analysis to describe and find the gap/discrepancy of students’ technical skills based on the predetermined standard. The results of the study show that the technical skills of vocational high school students in their industrial working practices are categorized as good with a low discrepancy based on the industrial assessment, and even better based on the students’ self-assessment. Yet there is a significant difference of technical skills among the vocational high school students in their industrial working practices based on the industrial work and students’ assessment with a significant value of 0.000 < 0,05.