Knowledge tracing is very important to improve personalized learning. "Knowledge tracing is the task of modeling student’s knowledge state, which is a general representation of the mastery level of KCs, e.g., a scalar value representing a student ability level, or a vector representation similar to word embedding." In knowledge tracing based on previous interactions next interaction is predicted. Usually we have question answer pairs as an interaction data and we want to predict the probability of answering the question correctly. The knowledge tracing models have 2 groups:

1. Models having direct meaningful parameters (Bayesian Knowledge Tracing (BKT), Performance Factor Analysis (PFA)).
2. Complex and general-purpose models which don't have direct interpretations.(Deep Knowledge Tracing (DKT) , Deep Key Value Memory Networdk (DKVMN)).

These groups are non-overlapping and the authors decided to create a new model, called Deep-IRT (Deep-Item Response Theory) which would make deep learning based knowledge explainable. The main contributions of this work (as written in the paper) are:

1. The proposed Deep-IRT knowledge tracing model is capable of inferring meaningful estimation of student ability and KCs’ difficulty level while simultaneously retains the predictive power of the deep learning based knowledge tracing model.

2. The Deep-IRT model potentially provides an alternative way for estimating KC’s difficulty level by utilizing the entire learning trajectory, rather than the traditional educational testing environment.

3. We propose to use a deep learning model to output parameters of a psychometric model so as to leverage the deep learning capability and provide explainable psychometric parameters. This idea can be applied elsewhere apart from the knowledge tracing task.