Koch's four-level evaluation is a very classic evaluation model in training evaluation, which divides the evaluation into four levels, namely, response evaluation, learning evaluation, behavior evaluation and result evaluation. Written test usually belongs to learning evaluation, that is, to evaluate students' mastery of knowledge and skills in training.

Learning evaluation is to evaluate students' mastery of knowledge and skills through written test, practical operation and simulation exercise after training. The purpose of learning evaluation is to determine whether students have mastered what they have learned, so as to prepare for the next behavioral evaluation and result evaluation. Therefore, the written test usually belongs to the second level of Koch's four-level assessment.

Generally speaking, the assessment of behavior level is to assess the extent to which trainees apply what they have learned and improve their behavior in practical work after updating their knowledge, improving their skills and improving their attitude by attending training courses three months and six months before the end of training courses. Behavioral evaluation is more difficult and costly than reaction and learning, but the importance of evaluation results can not be replaced by reaction and learning.

Generally speaking, the evaluation of behavior level is to investigate, understand and analyze the behavior differences of students before and after training by interviewing their immediate superiors, colleagues or customers who have business contacts, and whether these differences are really due to the role played by participating in training. At the same time, we should also investigate and understand students' own self-evaluation. Through the comprehensive analysis and demonstration of all kinds of information and data, we can get more objective evaluation results.

Although Koch's four-level evaluation model has many advantages, good universality and universality, there are obvious defects in the evaluation before training implementation.

However, in practical work, it is often necessary to evaluate training activities such as training demand analysis and training resource development before training is implemented. For example, it is very necessary to guide, review and control the implementation of the newly started important training projects before the implementation of the training. At this time, the Coriolis four-level evaluation model can not fully meet the needs of actual evaluation.

Therefore, in the evaluation work, we must borrow other evaluation models to supplement according to the specific situation and actual needs of training management or training projects, such as adding a training resource evaluation-pre-training evaluation to the three-stage evaluation model.