## 3 Materials and Methods
Since the correct answer will change every time the free parameter changes its value, a programming code must be included to allow the system to calculate the correct answer. In this case, the application is asking for a Matlab code. Figure 1: e-valUAM interface for teachers, showing the questions management window. Figure 2: e-valUAM interface for students, showing one question from a self-evaluating test in the subject Applied Computing. The question in English would read “Calculate the product of the following matrices and return the value of the determinant of the resulting matrix, where a = 4′′. In the case of the students' interface, we show an example of a question from the subject Applied Computing. As we can see, there is no information about the level of the question, since this is something internal to the algorithm. There is no information or clue about which parameter is changing, since the system already includes the calculated value in the question. In this case, the free parameter is a = 4. The dataset includes 396 instances of students from the academic courses 2017 to 2021, with a set of 110, 78, 79, 86 and 73 students each year in the first-year subject \"Applied Computing\" of the Degree in Chemical Engineering at the Universidad Autonoma de Madrid. This course corresponds to 6 ECTS. The total number of students (counting all of them) would be 426. However, some students did not finish their classes. For this reason, we only have 396 useful instances of students. Students' age is around 18-19 years old. This subject does not require any initial skill since it is a first-year course and starts from very basic programming contents. This dataset includes information from 7490 self-evaluation tests done by the students through the adaptive test platform [29]. These tests, done in their autonomous learning stage, can be done anytime between the beginning of the course and the final exam. Actually, a significant percentage of tests are performed the day before the final exam or even on the same day. Information extracted from the application includes the date and hour when every single test is performed. In this part, our goal is to check how continuous working is related to students' performance, extending the analysis to students from five academic years in a subject that did not change its methodology and contents in all that period (i.e., this subject had the same contents, teachers, teaching methods, exams and online material in the whole five academic courses). The only exception is that, due to the COVID-19 confinement, we have data from three scenarios that only change face-to-face or distant learning. 1. Pre-COVID-19. Both teaching and assessment were done face-to-face. This happened in academic years 2016/2017, 2017/2018 and 2018/2019;
2. COVID-19 confinement. Academic year 2019/2020;
3. Post-COVID-19 confinement. In academic year 2020/2021, students were not confined at their homes, so some restrictions could be softened. In the case of our subjects, teaching was online but final exams were face-to-face. In all of these academic years, students were able to use the online platform for autonomous study and final exams. The same questions have been used in Applied Computing tests, since their contents are related to numerical problems. In this case, open answer questions were developed with at least one free parameter that changes with each execution of the application. This kind of question requires the following elements:  
* A statement with an explicit indication of the modifiable parameter(s);
* Minimum and maximum values of each parameter;
* A programming code (Matlab in e-valUAM) that calculates the answer of the problem as a function of the values of the parameters  
It is also possible to include multimedia files. However, multimedia options are only available for the statement, as the answers can be numerical only.