Using previous years' papers to refine your approach to handling questions that require evaluating the significance of political events, treaties, and policies in PSIR (Political Science and International Relations) can be an effective strategy to improve your understanding and performance in this subject. Here is a detailed explanation on how to utilize these papers:

1. Identify the Relevant Questions:
- Begin by collecting previous years' papers from reliable sources such as UPSC's official website or EduRev.
- Carefully go through each question and identify those that require evaluating the significance of political events, treaties, and policies.
- Make a list of these questions for further analysis and practice.

2. Analyze the Questions:
- Once you have identified the relevant questions, analyze them thoroughly to understand the key aspects they focus on.
- Identify the specific political events, treaties, or policies mentioned in the questions.
- Pay attention to the context and scope of the questions to understand what is being asked.
- Note any recurring themes or patterns in the questions to gain insights into the important topics or areas of focus.

3. Research and Study:
- Conduct comprehensive research on the political events, treaties, and policies mentioned in the questions.
- Refer to textbooks, academic journals, reputable websites, and other relevant sources to gather in-depth knowledge about these topics.
- Make detailed notes and summaries to ensure a thorough understanding of the concepts, significance, and implications of the events, treaties, and policies.

4. Practice Answering:
- Once you have acquired a solid understanding of the topics, start practicing answering the identified questions.
- Set a time limit for each question to simulate the actual exam conditions.
- Use your research and knowledge to develop well-structured and coherent answers.
- Focus on providing a critical analysis of the significance of the political events, treaties, and policies rather than just stating facts.
- Regularly review and evaluate your answers to identify areas for improvement.

5. Learn from Model Answers:
- After attempting the questions, compare your answers with model answers available in reputable study materials or coaching institutes.
- Analyze the structure, content, and approach of the model answers to gain insights into effective answering techniques.
- Identify any gaps or weaknesses in your answers and work on improving them.

6. Repeat and Revise:
- Continue practicing with more previous years' papers to refine your approach and enhance your understanding of evaluating the significance of political events, treaties, and policies.
- Revise the topics regularly to reinforce your knowledge and ensure retention.

By following these steps, you can effectively utilize previous years' papers to refine your approach to handling questions related to evaluating the significance of political events, treaties, and policies in PSIR. Regular practice and thorough research will enhance your understanding and improve your performance in this subject.