input: The following are multiple choice questions (with answers) about medical knowledge.   **Question:** A type of fatal adrenal cancer has an average survival rate of 3 years after the onset of clinically significant symptoms. It is determined that patients have a 4-year asymptomatic period prior to developing clinical symptoms from this adrenal cancer. A new screening test is developed, and the cancer can now be detected 2 years prior to developing clinical symptoms. A new observational case-control study of screened and unscreened patients measures the median 5-year survival of patients who decline medical and surgical treatment. The screened population has statistically better outcomes. Which step should be undertaken to prevent bias in these conclusions?   (A) Using survival rates in the analysis   (B) Using mortality rates in the analysis   (C) Increasing the number of screened individuals   (D) Decreasing the number of screened individuals
output: ['(B) Using mortality rates in the analysis <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Using survival rates in the analysis  (B) Using mortality rates in the analysis  (C) Increasing the number of screened individuals  (D) Decreasing the number of screened individuals <> possible answers', '  A type of fatal adrenal cancer has an average survival rate of 3 years after the onset of clinically significant symptoms. It is determined that patients have a 4-year asymptomatic period prior to developing clinical symptoms from this adrenal cancer. A new screening test is developed, and the cancer can now be detected 2 years prior to developing clinical symptoms. A new observational case-control study of screened and unscreened patients measures the median 5-year survival of patients who decline medical and surgical treatment. The screened population has statistically better outcomes. Which step should be undertaken to prevent bias in these conclusions? <> context']