The evaluation criteria for College English Test Band 4 and Band 6 (CET-4 and CET-6) essays are designed to assess the quality of writing in terms of coherence, cohesion, vocabulary usage, grammar accuracy, and overall effectiveness. Below is a detailed breakdown of these criteria:

1. **Coherence and Cohesion**: This criterion evaluates how well the essay is organized and how effectively it conveys its message. Key aspects include:

- **Introduction**: The essay should have a clear introduction that presents the topic and outlines the main points.

- **Body Paragraphs**: Each paragraph should focus on a single idea or point, with logical transitions between paragraphs to maintain flow.

- **Conclusion**: The conclusion should summarize the main points and provide a strong closing statement.

2. **Vocabulary Usage**: This criterion assesses the range and appropriateness of vocabulary used in the essay. It includes:

- **Word Choice**: The use of varied and appropriate words to express ideas.

- **Precision**: The ability to use specific words that accurately convey meaning.

3. **Grammar Accuracy**: This criterion evaluates the correctness of sentence structure, word forms, tenses, and other grammatical elements. It includes:

- **Sentence Structure**: The use of complex sentences with varied structures.

- **Tense Consistency**: Proper use of tenses to maintain narrative coherence.

- **Word Forms**: Correct use of verb forms, noun forms, etc.

4. **Overall Effectiveness**: This criterion considers how well the essay achieves its purpose and engages the reader. It includes:

- **Relevance to Topic**: The essay should stay on topic throughout.

- **Clarity of Expression**: Ideas should be expressed clearly without ambiguity.

- **Engagement**: The essay should be engaging and interesting to read.

Scoring for each criterion is typically on a scale from 1 to 6, with 6 being the highest score. Essays are evaluated based on their overall quality in these areas, with special attention given to how well they meet the specific requirements of each test level (CET-4 or CET-6).

Understanding these criteria can help students prepare more effectively for their essays by focusing on key areas such as organization, vocabulary richness, grammatical accuracy, and overall impact.