Koch's four-level training evaluation model was put forward by Donald of the University of Wisconsin in the United States in 1959. It is the most widely used training evaluation tool in the world. Koch's four-level assessment is divided into four levels, including:

1, first-level evaluation, response evaluation, refers to the students' response to training preferences.

2. Secondary evaluation, learning evaluation, refers to how much knowledge, skills and attitudes students have gained after learning and training.

3. Three-level evaluation, that is, behavior evaluation, refers to the degree to which students apply what they have learned in training to their work to bring about behavioral changes.

4. Four-level evaluation and outcome evaluation are expected business outcomes brought by business outcome training and subsequent strengthening measures.