Comparing Median Lethal Concentration Values Using Confidence Interval Overlap or Ratio Tests

Details

• Personal Author:
  Bailer AJ ; Park RM ; Wheeler, Matthew W.
• Description:
  Experimenters in toxicology often compare the concentration-response relationship between two distinct populations using the median lethal concentration (LC50). This comparison is sometimes done by calculating the 95% confidence interval for the LC50 for each population, concluding that no significant difference exists if the two confidence intervals overlap. A more appropriate test compares the ratio of the LC50s to 1 or the log(LC50 ratio) to 0. In this ratio test, we conclude that no difference exists in LC50s if the confidence interval for the ratio of the LC50s contains 1 or the confidence interval for the log(LC50 ratio) contains 0. A Monte Carlo simulation study was conducted to compare the confidence interval overlap test to the ratio test. The confidence interval overlap test performs substantially below the nominal alpha = 0.05 level, closer to p = 0.005; therefore, it has considerably less power for detecting true differences compared to the ratio test. The ratio-based method exhibited better type I error rates and superior power properties in comparison to the confidence interval overlap test. Thus, a ratio-based statistical procedure is preferred to using simple overlap of two independently derived confidence intervals. [Description provided by NIOSH]
• Subjects:
  Animals Occupational Health Safety Toxicology
• Keywords:
  Comparative-toxicology Mathematical-models Statistical-analysis Statistical-quality-control
• ISSN:
  0730-7268
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  EID - Education and Information Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  25
• Issue:
  5
• NIOSHTIC Number:
  nn:20030995
• Citation:
  Environ Toxicol Chem 2006 May; 25(5):1441-1444
• Contact Point Address:
  National Institute for Occupational Safety and Health, 4676 Columbia Parkway MS-15, Cincinnati, Ohio 45226, USA
• Email:
  mwheeler@cdc.gov
• Federal Fiscal Year:
  2006
• NORA Priority Area:
  Research Tools and Approaches: Risk Assessment Methods
• Peer Reviewed:
  True
• Source Full Name:
  Environmental Toxicology and Chemistry
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:2c62e5df18e9bc7a1adc9623aa0b6c0552da48159b11a05c9cfb3ad28a57b45ab7be89293bd1e5dece6fb3626b7700ff2015605f8c6b6eaf5fe731cd809c601c
• Download URL:
  https://stacks.cdc.gov/view/cdc/191401/cdc_191401_DS1.pdf
• File Type:
  [PDF - 53.15 KB ]