title: Statistical issues in the analysis of low-dose endocrine disruptor data.
abstract: The National Institute of Environmental Health Sciences (NIEHS) and the U.S. Environmental Protection Agency (U.S. EPA) recently cosponsored the Endocrine Disruptors Low-Dose Peer
  
  
  METHODS
  The purpose of this meeting was to examine data supporting the presence or absence of low-dose effects of endocrine disruptors in specific studies and then to evaluate the likelihood and significance of these and/or other potential low-dose effects for humans. All invited speakers agreed to provide their raw data in advance of the meeting to a Statistics Subpanel, which was asked to reevaluate the authors' experimental design, data analysis, and interpretation of experimental results. The purpose of this statistical reevaluation was to provide an independent assessment of the experimental design and data analysis used in each of the studies and to identify key statistical issues relevant to the evaluation and interpretation of the data. This paper presents a summary of the Statistics Subpanel's evaluation. Specific examples are presented to illustrate problems that arose in the experimental design and data analysis of certain studies. The statistical principles and issues that are discussed in this paper are not unique to endocrine disruptor studies and should provide important guidelines regarding appropriate experimental design and statistical analysis for other types of laboratory investigations.
authors.affiliation: Biostatistics Branch, National Institute of Environmental Health Sciences, PO Box 12233, Research Triangle Park, North Carolina 27709, USA. haseman@niehs.nih.gov
authors.forename: J K
authors.initials: JK
authors.lastname: Haseman
authors.forename: A J
authors.initials: AJ
authors.lastname: Bailer
authors.forename: R L
authors.initials: RL
authors.lastname: Kodell
authors.forename: R
authors.initials: R
authors.lastname: Morris
authors.forename: K
authors.initials: K
authors.lastname: Portier
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight / Q000187:drug effects*; D003625:Data Collection; D004305:Dose-Response Relationship, Drug; D004702:Endocrine Glands / Q000187:drug effects*; D004785:Environmental Pollutants / Q000633:toxicity; D005260:Female; D006801:Humans; D008297:Male; D009316:National Institutes of Health (U.S.); D009929:Organ Size / Q000187:drug effects*; D011247:Pregnancy; D012107:Research Design; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D014481:United States; D014484:United States Environmental Protection Agency
chemical_list: D004785:Environmental Pollutants