THE IPCS COLLABORATIVE STUDY ON NEUROBEHAVIORAL SCREENING METHODS - VI - AGREEMENT AND RELIABILITY OF THE DATA

The IPCS Collaborative Study on Neurobehavioral Screening Methods was undertaken to determine the intra-and inter-laboratory reliability of a functional observational battery (FOB) and an automated assessment o f motor activity in eight laboratories world-wide. The effects of seve n chemicals (acrylamide, bis-acrylamide, p,p'-DDT, lead acetate, parat hion, toluene, and triethyl tin) were studied during two dosing regime ns: single-dose and four-week repeated dosing. All participating labor atories generally could detect and characterize the effects of known n eurotoxicants, even though there were some differences in outcome on s pecific endpoints. The results were further evaluated to assess the ag reement across laboratories in the dose-response data at the expected times of maximal effect (time of peak effect for the single-dose studi es, and during or at the end of dosing for repeated-exposure studies). Percent agreement was calculated as the percentage of laboratories ag reeing on an outcome (whether it be a significant dose effect or not). As an alternative approach, slopes of the dose-response functions wer e calculated, and reliability of those slope estimates across laborato ries and chemicals was determined. Reliability was defined as the degr ee of agreement across laboratories (intra-class correlation coefficie nt) of the dose-response slopes within and between chemicals. These re liability estimates were calculated for each domain and for each endpo int. Relative reliability of the endpoints was evaluated, and hypothes es concerning the influence of outlying data were tested. The data cle arly showed that reliability was not influenced by the objectivity or subjectivity of the test measure. Thus these data provide additional i nformation regarding the reliability and robustness of the tests acros s the participating laboratories. (C) 1997 Intox Press, Inc.