Instructions: Given a passage with a question and an answer to that question, classify if the answer actually answers the question into 'yes' or 'no'. Output 'yes' if the answer answers the question and output 'no' if the answer does not answer the question.
Input: Question: Do increased insomnia symptoms predict the onset of back pain among employed adults?
Answer: Insomnia appears to be a risk factor in the development of back pain in healthy individuals. However, no evidence of reverse causation was found.
Output:
yes