Every time a student opens the practice tool, a question is loaded automatically. The authors modified the SuperMemo 2 (SM-2) algorithm, which uses the following parameters to update question $y$ for student $x$:

1. $i\_interval_{xy}$: The number of days remaining before asking question $y$ to student $x$.
2. $e\_factor_{xy}$: The easiness factor (E-factor) of question $y$ for student $x$.
3. $q_{xy}$: The response quality score of student $x$'s answer to question $y$, represented as an integer from 1 to 5.

Modifications

1. Topic-level Scheduling: The algorithm is applied to entire topics instead of single questions, and individual questions within a topic are delivered using round-robin scheduling.
2. Behavior-Based Response Quality ($q_{xy}$): In the original SM-2 algorithm, $q_{xy}$ is based purely on the correctness of the answer. In this modified tool, the authors calculate $q_{xy}$ using three behavioral factors:
   • $d_{xy}$: The duration of time student $x$ spent answering question $y$, measured in minutes.
   • $t_{xy}$: The number of attempts student $x$ made before submitting their final answer for question $y$.
   • $v_{xy}$: The number of other textbook pages viewed while answering question $y$.

The value of $q_{xy}$ is determined as follows:

• (1) $q_{xy} = 5$ if $v_{xy} = 0$, $t_{xy} \le 1$, and $d_{xy} \le 2$
• (2) $q_{xy} = 4$ if $t_{xy} \le 2$ and $d_{xy} \le 2$
• (3) $q_{xy} = 3$ if $t_{xy} \le 3$ and $d_{xy} \le 3$
• (4) $q_{xy} = 2$ if $t_{xy} \le 4$ and $d_{xy} \le 4$
• (5) $q_{xy} = 1$ if correct, but other conditions are not met
• (6) $q_{xy} = 0$ if the final answer is incorrect