Why Your RAG Chatbot Gives Wrong Answers (And How to Fix It)

说明与用途

RAG 聊天机器人经常给出错误答案，原因是检索不当。通过调整块大小、添加重叠、清理提取文本以及对扫描 PDF 进行 OCR，可以解决此问题。

问题

RAG chatbots often return incorrect or fabricated answers because the retrieval step fails to provide the correct document excerpts.

结果

By tuning chunk size, adding overlap, cleaning extracted text, and handling scanned PDFs, the RAG chatbot’s retrieval accuracy improved, leading to more correct answers.

工作流

• 1. Print the retrieved chunks to inspect their content.
• 2. Adjust chunk size to 300‑500 words and test multiple sizes.
• 3. Add overlap of ~50 words between chunks to avoid sentence splits.
• 4. Extract text from PDF using pdfplumber and inspect for noise.
• 5. Remove repeated header/footer lines using a frequency counter.
• 6. Detect empty or short pages and flag potential scanned PDFs.
• 7. If scanned, apply OCR (e.g., pytesseract) before extraction.
• 8. Rebuild the index with cleaned chunks and retest queries.

证据

If the answer is not in those pieces, fix retrieval (problems 1 to 4 and 7 below).

来源

Fix: start with about 300 to 500 words per chunk.

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let each chunk repeat the last 50 words or so of the one before it.

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If the text you extract is bad, everything after it is bad too.

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